AD 685 Boston University Univariate Statistics Term Paper Project

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Term Paper:

Using the knowledge that the student acquires during the course, the student will prepare an empirical research paper.

The papers should not exceed 15 double spaced pages, not including cover page and appendices.

Papers are to be RESEARCH PAPERS. Remember that work that you use from other authors MUST be referenced. Since it is assumed that you are not an authority on the topic that you are writing, it is expected that this paper is an overview of many different sources of information. These must be contributed to the author using the APA format.

This is your paper and not the cut and paste of someone else’s work. The internet has led to a false sense of what research is all about. Those new to research tend to think that it means spending an afternoon surfing the internet and then an afternoon cutting from material available. Keep in mind that the Internet is: (1) not quality oriented as it has good materials and not so good materials, and the Internet does not know the difference; (2) the Internet is NOT a sole source location. In particular, sources such as Wikipedia are the works of individual submitters which are not reviewed. Thus while many entries provide excellent information, some are fundamentally flawed or just plain wrong. Keep in mind that the Boston University Library as well as your local, state and the national US Library of Congress have extensive online services. USE THEM.

The research paper must include a bibliography of information and works cited.

The paper should be prepared using the APA writing style and guideline for references’ format. You must provide a bibliography, and all direct quotations and data sources must be properly cited. The Department uses the APA style as to facilitate both, reading the paper and understanding references without being cumbersome as some of the other styles (such as Chicago or MLA). Students can download the student style guide from APA Style® Help) web site.

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EC420 Michigan State University Econometric Method & Scaling Data Essay

Economics 420 Introduction to Econometrics Professor Woodbury — Fall Semester 2019 Model Specification 1. What is “model specification”? 2. Scaling data 3. Models with quadratics 4. What if X is a “dummy” (binary) variable? 5. Dummy variables for multiple categories … more to come 1 1. What is “model specification”? Model specification refers to: • the variables included in a model • how each of those variables is “specified” — linearly, as a log, as a quadratic, as a dummy variable, interacted with one or more other variables The earnings function is a canonical example: • how should earnings be specified? • which variables should be included? • how should they appear in the equation? 2 2. Scaling data (units of measurement) (Wooldridge, sections 2.4, 6.1) Yi = β0 + β1X1i + β2X2i + … + βkXki + ui, • It is often convenient to change the units of measurement to make the estimates from a model easier to interpret • For example, you may want to estimate the relationship between spending per student and math pass rate (MEAP93.dta) • But spending per student in measured in dollars, and the estimated coefficient may be very small • Rescaling the variable may make the results clearer 3 Main results to remember • When the dependent variable changes units of measurement: o Y • c (where c is a constant) means that the intercept and all the slope coefficients will be multiplied by c o Y / c (where c is a constant) means that the intercept and all the slope coefficients will be divided by c • So multiplying the dependent variable by a constant means the intercept and all the coefficients get multiplied by that constant • Dividing the dependent variable by a constant means the intercept and all the coefficients get divided by that constant 4 Example: CEOSAL1.dta (regress salary on roe) salary roe int float %9.0g %9.0g 1990 salary, thousands $ return on equity, 88-90 avg . sum salary roe Variable | Obs Mean Std. Dev. Min Max ————-+——————————————————–salary | 209 1281.12 1372.345 223 14822 roe | 209 17.18421 8.518509 .5 56.3 . reg salary roe Source | SS df MS ————-+———————————Model | 5166419.04 1 5166419.04 Residual | 386566563 207 1867471.32 ————-+———————————Total | 391732982 208 1883331.64 Number of obs F(1, 207) Prob > F R-squared Adj R-squared Root MSE = = = = = = 209 2.77 0.0978 0.0132 0.0084 1366.6 —————————————————————————–salary | Coef. Std. Err. t P>|t| [95% Conf. Interval] ————-+—————————————————————roe | 18.50119 11.12325 1.66 0.098 -3.428196 40.43057 _cons | 963.1913 213.2403 4.52 0.000 542.7902 1383.592 —————————————————————————— 5 • What if we rescale salary to dollars (from $1,000s)? . gen salarydol = salary * 1000 . sum salary salarydol roe Variable | Obs Mean Std. Dev. Min Max ————-+——————————————————–salary | 209 1281.12 1372.345 223 14822 salarydol | 209 1281120 1372345 223000 1.48e+07 roe | 209 17.18421 8.518509 .5 56.3 . reg salarydol roe Source | SS df MS ————-+———————————Model | 5.1664e+12 1 5.1664e+12 Residual | 3.8657e+14 207 1.8675e+12 ————-+———————————Total | 3.9173e+14 208 1.8833e+12 Number of obs F(1, 207) Prob > F R-squared Adj R-squared Root MSE = = = = = = 209 2.77 0.0978 0.0132 0.0084 1.4e+06 —————————————————————————–salarydol | Coef. Std. Err. t P>|t| [95% Conf. Interval] ————-+—————————————————————roe | 18501.19 11123.25 1.66 0.098 -3428.196 40430.57 _cons | 963191.3 213240.3 4.52 0.000 542790.2 1383592 —————————————————————————— 6 • When an independent variable changes units of measurement: o X • c (where c is a constant) means the coefficient on that X will be divided by c o X / c (where c is a constant) means the coefficient on that X will be multiplied by c • So multiplying an independent variable by a constant means the coefficient on that variable gets divided by the same constant • Dividing an independent variable by a constant means the coefficient on that variable gets multiplied the same constant 7 Example: MEAP93.dta (regress math10 on expend) math10 expend float int %9.0g %9.0g perc studs passing MEAP math expend. per stud, $ . sum math10 expend Variable | Obs Mean Std. Dev. Min Max ————-+——————————————————–math10 | 408 24.10686 10.49361 1.9 66.7 expend | 408 4376.578 775.7897 3332 7419 . reg math10 expend Source | SS df MS ————-+———————————Model | 1477.19666 1 1477.19666 Residual | 43339.9838 406 106.748729 ————-+———————————Total | 44817.1805 407 110.115923 Number of obs F(1, 406) Prob > F R-squared Adj R-squared Root MSE = = = = = = 408 13.84 0.0002 0.0330 0.0306 10.332 —————————————————————————–math10 | Coef. Std. Err. t P>|t| [95% Conf. Interval] ————-+—————————————————————expend | .0024557 .0006601 3.72 0.000 .001158 .0037534 _cons | 13.35923 2.934111 4.55 0.000 7.591287 19.12718 —————————————————————————— 8 • But it may be easier to think about expenditures per students in $1,000s — divide expend by 1,000 . gen expendthou = expend / 1000 . sum math10 expend expendthou Variable | Obs Mean Std. Dev. Min Max ————-+——————————————————–math10 | 408 24.10686 10.49361 1.9 66.7 expend | 408 4376.578 775.7897 3332 7419 expendthou | 408 4.376578 .7757897 3.332 7.419 . reg math10 expendthou Source | SS df MS ————-+———————————Model | 1477.19667 1 1477.19667 Residual | 43339.9838 406 106.748729 ————-+———————————Total | 44817.1805 407 110.115923 Number of obs F(1, 406) Prob > F R-squared Adj R-squared Root MSE = = = = = = 408 13.84 0.0002 0.0330 0.0306 10.332 —————————————————————————–math10 | Coef. Std. Err. t P>|t| [95% Conf. Interval] ————-+—————————————————————expendthou | 2.455715 .6601462 3.72 0.000 1.157983 3.753446 _cons | 13.35923 2.934111 4.55 0.000 7.591287 19.12718 —————————————————————————–9 3. Models with quadratics (Wooldridge, section 6.2) Consider the following model: E(Y) = β0 + β1X + β2X2 What is the relationship between X and Y in this model? ΔE(Y ) = β1 + 2β 2 X ΔX • What does this tell you? • The relationship depends on the level of X 10 ΔE(Y ) = β1 + 2β 2 X ΔX • Suppose X = 0, then ΔE(Y ) = β1 ΔX • Otherwise the value of X matters (as long as β2 ≠ 0) • A common approach for obtaining a summary of ΔE(Y)/ΔX is to plug in the mean value of X into the expression at the top of this slide and calculate ΔE(Y)/ΔX for that value 11 Example • The so-called Mincer earnings equation combines the log transformation with a quadratic specification of experience • In the following earnings equation, look at the relationship between log(earnings) and experience, and calculate the level of experience for which log(earnings) is a maximum: log(earnings) = β0 + β1educ + β2exper + β3exper2 + u • Typically in an earnings equation, we have: β2 > 0 and β3 < 0 so the experience-earnings profile starts with a positive (but decreasing) slope that reaches a maximum, then falls 12 • To find the turning point, use a little calculus: ∂log(earnings) = β 2 + 2β3exper ∂exper • Set this expression to 0 and solve for exper: β 2 + 2β3exper = 0 −β2 exper = 2β3 • So if β2 = 0.041 and β3 = –0.00071 (as in WAGE1.dta), earnings max out after 28.9 years of experience 13 Questions What is the return to experience when exper = 0? What is the return to experience when exper = 1? What is the return to experience when exper = 5? What is the return to experience when exper = 10? What is the return to experience when exper = 20? What is the return to experience when exper = 30? 14 Solution for the return to experience when exper = 10 Apply the formula: ΔE(Y ) = β1 + 2β 2 X ΔX In this case, ∂log(earnings) = β 2 + 2β3exper ∂exper = 0.041 + 2(–0.00071)•exper = 0.041 + (–0.00142)•10 = 0.041 – 0.0142 = 0.0268 So, for someone with 10 years of experience, the expected return to an additional year of experience is ~2.7 percent 15 Another example • A study of the relationship between alcohol and health in Lancet takes little care in matching results with conclusions (courtesy of Professor Imberman) • https://urldefense.proofpoint.com/v2/url? u=https-3A__mobile.twitter.com_scottimberman_status_10330438 28717092865&d=DwICAg&c=nE__W8dFEshTxStwXtp0A&r=5gNfshNzZWFcbhoDspnU-A&m=wSiArarzsSlua1mFTRSmOmIF3zVBRsAbtvY52kJtUs&s=t7O1zf7xvyRnDzCegXb hRwc0lvHvh5ULadg23oKcjJ0&e= • The figure shows the weighted relative risk of death or disability from alcohol, by standard drinks consumed per day 16 rve, we tandard l health ly with weighted e effects disease otective cancers, on. In a 4·5 4·0 3·5 Relative risk men and tandard daily for relative diabetes her outtive risk umption 3·0 2·5 2·0 1·5 1·0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Standard drinks daily Figure 5: Weighted relative risk of alcohol for all attributable causes, by standard drinks consumed per day 17 • “In 2016, alcohol use led to 2.8 million deaths and was the leading risk factor for premature death and disability among people aged 15–49 years, with nearly 9% of all attributable DALYs (deaths and disability-adjusted life-years) for men and more than 2% for women.” • Two problems: first, the study draws conclusions that could only be made if the study were causal — it takes little care in matching results with conclusions 18 • Second, it ignores the nonlinearity in the effect of alcohol consumption on health • “… the level of consumption that minimizes health loss is zero.” • The dotted line is a reference line for a relative risk of 1 (DALYs = deaths and disability-adjusted life-years) • Comment (Aaron E. Carroll @aaronecarroll): “Can someone please explain to me how a figure that shows that at one drink per day you have a relative risk of 1 can lead to the conclusion that there is no safe level of alcohol consumption?” 19 4. What if X is a “dummy” (binary) variable? (Wooldridge, sections 7.1, 7.2) • Dummy variables (aka zero-one, binary, or indicator variables) are useful when you need to model something that is qualitative or categorical X = 1 if female, 0 if male X = 1 if treated (experimental drug), 0 if not X = 1 if small class size, 0 if not 20 • Other examples Race or ethnicity (Caucasian, African-American, Asian, Hispanic) o Marital status (married, never married, separated, divorced, widowed) o Industry or occupation • Things are easy when there are only two categories (male or female), but can be a little more involved when there are many (the other examples—for later) • So far, β1 has been called a “slope,” but that doesn’t make sense if X is binary • How do we interpret regression with a binary regressor? o 21 Back to a simple regression: Yi = β0 + β1Xi + ui • If X is binary (Xi = 0 or 1), then when Xi = 0: Yi = β0 + ui when Xi = 1: Yi = β0 + β1 + ui • so: when Xi = 0, the mean of Yi is β0 when Xi = 1, the mean of Yi is β0 + β1 • or (equivalently): E(Yi | Xi = 0) = β0 E(Yi | Xi = 1) = β0 + β1 22 So we have this result: • When Yi = β0 + β1Xi + ui and X is binary: E(Yi) = β0 when Xi = 0 E(Yi) = β0 + β1 when Xi = 1 • So β1 = E(Yi | Xi = 1) – E(Yi | Xi = 0) = population difference between mean Y for group 1 and mean Y for group 2 or the expected difference between the two group means 23 • SE( β̂1 ) has the usual interpretation o t-statistics, p-values, and confidence intervals constructed as usual Examples • Differences in wages by gender, race, and marital status — see Examples 7.1, 7.6, 7.10, 7.11 in Wooldridge • Experimental effects (difference-in-means analysis — reemployment bonus experiment — see below) 24 Wooldridge Example 7.1—Gender wage gaps use WAGE1.DTA reg wage female Source | SS df MS ————-+—————————–Model | 828.220467 1 828.220467 Residual | 6332.19382 524 12.0843394 ————-+—————————–Total | 7160.41429 525 13.6388844 Number of obs F( 1, 524) Prob > F R-squared Adj R-squared Root MSE = = = = = = 526 68.54 0.0000 0.1157 0.1140 3.4763 —————————————————————————–wage | Coef. Std. Err. t P>|t| [95% Conf. Interval] ————-+—————————————————————female | -2.51183 .3034092 -8.28 0.000 -3.107878 -1.915782 _cons | 7.099489 .2100082 33.81 0.000 6.686928 7.51205 —————————————————————————— for difference of means, use the Stata command: ttest wage, by (female) 25 reg wage female educ exper tenure Source | SS df MS ————-+—————————–Model | 2603.10658 4 650.776644 Residual | 4557.30771 521 8.7472317 ————-+—————————–Total | 7160.41429 525 13.6388844 Number of obs F( 4, 521) Prob > F R-squared Adj R-squared Root MSE = = = = = = 526 74.40 0.0000 0.3635 0.3587 2.9576 —————————————————————————–wage | Coef. Std. Err. t P>|t| [95% Conf. Interval] ————-+—————————————————————female | -1.810852 .2648252 -6.84 0.000 -2.331109 -1.290596 educ | .5715048 .0493373 11.58 0.000 .4745803 .6684293 exper | .0253959 .0115694 2.20 0.029 .0026674 .0481243 tenure | .1410051 .0211617 6.66 0.000 .0994323 .1825778 _cons | -1.567939 .7245511 -2.16 0.031 -2.991339 -.144538 —————————————————————————— 26 Another example: Difference-in-means analysis using dummy variables • Dummy variables give you a simple way to do difference-inmeans analysis — especially useful when we have additional regressors • Problem: Unemployment insurance (UI) may induce recipients to search less hard for a job and take longer to become reemployed (moral hazard effect) • This is a problem both for the worker (longer spell of unemployment, lower earnings, possibly lower earnings in the long-term) and for the UI system (more benefits paid) 27 • One policy to ameliorate this problem is the reemployment bonus (or job search incentive) — a lump sum paid to a UI claimant who finds and job within a specified number of weeks, and who holds the job for a minimum number of months following reemployment • First reemployment bonus: Illinois in the 1980s o o Maximum potential duration of benefits in Illinois: 26 weeks Terms of the reemployment bonus: $500 cash if you find a job within 11 weeks and hold the job for 4 months 28 • An alternative policy (also tried in Illinois but not thereafter) is a hiring incentive bonus — each UI claimant told to inform prospective employers, “Hire me within 11 weeks, and employ me for at least 4 months, and you will receive a $500 payment from the State of Illinois.” • How do you evaluate policies like these? • Random assignment! 29 • In Illinois, new UI claimants randomly assigned to one of three groups o o o Control group (treated like a normal UI claimants) Offered a job search incentive bonus Offered a hiring incentive bonus • How do you know whether one (or both) of the programs worked? • Compare mean outcome(s) of controls and those who received the treatment 30 (Illinois bonus extract (FSC ineligibles)) 2 . drop if hie==1 (1581 observations deleted) Two ways of calculating experimental effects 3 . ttest wkpaid, by jsie comparison of means • Straight option by incorrectly specified r(198); o In Stata, ttest outcome, by (treatment) 4 . ttest wkpaid, by (jsie) Two-sample t test with equal variances Group Obs Mean 0 1 1725 1735 combined 3460 diff Std. Err. Std. Dev. [95% Conf. Interval] 16.86145 15.83516 .2384533 .2478865 9.903709 10.3253 16.39376 15.34897 17.32914 16.32135 16.34682 .1721957 10.12886 16.00921 16.68444 1.026291 .3440003 .3518265 1.700755 diff = mean(0) – mean(1) Ho: diff = 0 Ha: diff < 0 Pr(T < t) = 0.9986 5 . t = degrees of freedom = Ha: diff != 0 Pr(|T| > |t|) = 0.0029 2.9834 3458 Ha: diff > 0 Pr(T > t) = 0.0014 31 wkpaid Coef. jsie _cons -1.026291 16.86145 Std. Err. .3440003 .2435962 • Dummy variable regression o t -2.98 69.22 P>|t| 0.003 0.000 [95% Conf. Interval] -1.700755 16.38384 -.3518265 17.33906 reg outcome treatment, robust 7 . reg wkpaid jsie, robust Linear regression Number of obs F( 1, 3458) Prob > F R-squared Root MSE wkpaid Coef. jsie _cons -1.026291 16.86145 Robust Std. Err. .3439589 .2384531 t -2.98 70.71 P>|t| 0.003 0.000 = = = = = 3460 8.90 0.0029 0.0026 10.117 [95% Conf. Interval] -1.700674 16.39393 -.3519077 17.32897 8 . 32 • Adding control variables (age, education, etc.) to the preceding regression would reduce the sampling variation in β1-hat, so the standard error of β1-hat should fall • Why? Remember: 2 σ var( β̂ j ) = σ β̂2 = j SSTj (1− R 2j ) and adding control variables reduces σ2 33 Other points about the Illinois data • Treatment effects for other outcomes (including pre- and post-program earnings) could be estimated • Important to check for balance in the treatment groups (are the variable means similar in the control and treatment groups?) • How many received bonuses? 34 5. Dummy variables for multiple categories See Wooldridge, section 7.3 (especially “Incorporating ordinal information by using dummy variables” and Example 7.7) A very short review • Dummy variables (zero-one, binary, or indicator variables) are useful when you need to model something that is qualitative or categorical X = 1 if female, 0 if male X = 1 if treated (experimental drug), 0 if not X = 1 if small class size, 0 if not 35 • When Yi = β0 + β1Xi + ui and X is binary: β0 = mean of Y for X = 0 β0 + β1 = mean of Y for X = 1 β1 = difference in group means = E(Yi | Xi = 1) – E(Yi | Xi = 0) 36 • Other examples Race or ethnicity (Caucasian, African-American, Asian, Hispanic) o Marital status (married, never married, separated, divorced, widowed) o Industry or occupation • Things are easy when there are only two categories (male or female), but can be a little more involved when there are many (the other examples) o 37 Looks (or “beauty”) and earnings • The data in BEAUTY.dta provide a good example • These data come from Daniel Hamermesh and Jeff Biddle, “Beauty and the Labor Market,” American Economic Review 84 (1994): 1174-1194 • The variable looks in this dataset is ordinal • The five categories are: homely (1), quite plain (2), average (3), good looking (4), and strikingly beautiful/handsome (5) • We will look at three possible specifications of looks 38 • Here is the distribution of looks in this sample . tab looks from 1 to 5 | Freq. Percent Cum. ————+———————————-1 | 13 1.03 1.03 2 | 142 11.27 12.30 3 | 722 57.30 69.60 4 | 364 28.89 98.49 5 | 19 1.51 100.00 ————+———————————-Total | 1,260 100.00 • Would you want to include looks as is (1–5)? log(wage) = β0 + β1educ + β2exper + β3exper2 + β4female + β5looks + u (1) In this model, looks is the original ordinal variable 39 • Or is another approach better? For example, log(wage) = β0 + β1educ + β2exper + β3exper2 + β4female + β5looks1 + β6looks2 + β7looks3 + β8looks4 + β9looks5 + u (2) In this model looks1 = 1 if looks = 1 (0 otherwise) looks2 = 1 if looks = 2 (0 otherwise) looks3 = 1 if looks = 3 (0 otherwise) looks4 = 1 if looks = 4 (0 otherwise) looks5 = 1 if looks = 5 (0 otherwise) So looks1 … looks5 are five mutually exclusive and exhaustive dummy variables capturing all the information in looks 40 • Here is a third possible specification log(wage) = β0 + β1educ + β2exper + β3exper2 + β4female + β5belavg + β6avg + β7abvavg + u (3) This is Biddle and Hamermesh’s preferred specification, where belavg = 1 if looks = 1 or 2 (0 otherwise), avg = 1 if looks = 3 (0 otherwise) abvavg = 1 if looks = 4 or 5 (0 otherwise) • Estimates of the three models follow 41 • Here is the model with the original variable (looks) included — equation (1) • Why is this not a good way to specify the model? . reg lwage educ exper expersq looks Source | SS df MS ————-+—————————–Model | 103.347555 4 25.8368886 Residual | 341.632418 1255 .272217066 ————-+—————————–Total | 444.979972 1259 .353439215 Number of obs F( 4, 1255) Prob > F R-squared Adj R-squared Root MSE = = = = = = 1260 94.91 0.0000 0.2323 0.2298 .52174 —————————————————————————–lwage | Coef. Std. Err. t P>|t| [95% Conf. Interval] ————-+—————————————————————educ | .0683689 .0058127 11.76 0.000 .0569653 .0797725 exper | .0487326 .0047884 10.18 0.000 .0393386 .0581267 expersq | -.0006985 .0001077 -6.49 0.000 -.0009097 -.0004872 looks | .0620681 .0219232 2.83 0.005 .019058 .1050782 _cons | .0462774 .105333 0.44 0.660 -.1603708 .2529255 —————————————————————————— 42 • Here is the model with all five looks categories included as dummies — equation (2) • Notice that Stata drops one category (Why?) . reg lwage educ exper expersq looks1 looks2 looks3 looks4 looks5 note: looks5 omitted because of collinearity Source | SS df MS ————-+—————————–Model | 106.116516 7 15.1595023 Residual | 338.863456 1252 .270657712 ————-+—————————–Total | 444.979972 1259 .353439215 Number of obs F( 7, 1252) Prob > F R-squared Adj R-squared Root MSE = = = = = = 1260 56.01 0.0000 0.2385 0.2342 .52025 —————————————————————————–lwage | Coef. Std. Err. t P>|t| [95% Conf. Interval] ————-+—————————————————————educ | .0682993 .0058026 11.77 0.000 .0569154 .0796833 exper | .0484757 .0047766 10.15 0.000 .0391048 .0578467 expersq | -.0006987 .0001074 -6.50 0.000 -.0009094 -.000488 looks1 | -.4653829 .1889268 -2.46 0.014 -.836031 -.0947348 looks2 | -.3025159 .1275879 -2.37 0.018 -.5528256 -.0522061 looks3 | -.1358712 .1213901 -1.12 0.263 -.3740217 .1022793 looks4 | -.1556256 .1225351 -1.27 0.204 -.3960224 .0847711 looks5 | 0 (omitted) _cons | .4113932 .145361 2.83 0.005 .1262153 .6965712 43 It usually makes sense to omit a category (rather than let Stata do it for you) — then you choose the reference category . reg lwage educ exper expersq looks1 looks2 Source | SS df MS ————-+—————————–Model | 106.116516 7 15.1595023 Residual | 338.863456 1252 .270657712 ————-+—————————–Total | 444.979972 1259 .353439215 looks4 looks5 Number of obs F( 7, 1252) Prob > F R-squared Adj R-squared Root MSE = = = = = = 1260 56.01 0.0000 0.2385 0.2342 .52025 —————————————————————————–lwage | Coef. Std. Err. t P>|t| [95% Conf. Interval] ————-+—————————————————————educ | .0682993 .0058026 11.77 0.000 .0569154 .0796833 exper | .0484757 .0047766 10.15 0.000 .0391048 .0578467 expersq | -.0006987 .0001074 -6.50 0.000 -.0009094 -.000488 looks1 | -.3295117 .1464298 -2.25 0.025 -.6167865 -.042237 looks2 | -.1666447 .0478185 -3.48 0.001 -.2604578 -.0728315 looks4 | -.0197544 .0339561 -0.58 0.561 -.0863716 .0468627 looks5 | .1358712 .1213901 1.12 0.263 -.1022793 .3740217 _cons | .2755221 .0845305 3.26 0.001 .109685 .4413591 —————————————————————————— 44 Finally, here is the model with looks specified using belavg and abvavg — equation (3) . reg lwage educ exper expersq belavg abvavg Source | SS df MS ————-+—————————–Model | 105.369105 5 21.0738209 Residual | 339.610868 1254 .270822063 ————-+—————————–Total | 444.979972 1259 .353439215 Number of obs F( 5, 1254) Prob > F R-squared Adj R-squared Root MSE = = = = = = 1260 77.81 0.0000 0.2368 0.2338 .52041 —————————————————————————–lwage | Coef. Std. Err. t P>|t| [95% Conf. Interval] ————-+—————————————————————educ | .0687694 .0057921 11.87 0.000 .0574061 .0801327 exper | .0483835 .0047764 10.13 0.000 .0390129 .0577542 expersq | -.0006996 .0001074 -6.51 0.000 -.0009104 -.0004889 belavg | -.1800631 .0461625 -3.90 0.000 -.2706273 -.0894988 abvavg | -.012913 .0334551 -0.39 0.700 -.0785471 .0527212 _cons | .2719752 .0844519 3.22 0.001 .1062927 .4376577 —————————————————————————— 45 Points to note • What are the problems with (1) — using an ordinal variable (looks) as independent variable? o What restrictive assumption are you imposing? • Is (2) better? o Can you estimate all five coefficients? No o It leads you into a “dummy variable trap” o You need to interpret the coefficient estimates with respect to the reference group — the omitted category • Why did Biddle and Hamermesh prefer (3)? o Look at the distribution of looks (see output following the Stata “tab” command, repeated below) 46 . tab looks from 1 to 5 | Freq. Percent Cum. ————+———————————-1 | 13 1.03 1.03 2 | 142 11.27 12.30 3 | 722 57.30 69.60 4 | 364 28.89 98.49 5 | 19 1.51 100.00 ————+———————————-Total | 1,260 100.00 47 Key point again • In specifications (2) and (3), one category necessarily drops out due to the perfect collinearity (the “dummy variable trap” • The coefficient estimates are interpreted with respect to the reference group — the omitted category • For example, in specification (3) belavg = –0.180 (0.046) o Interpretation: Other things equal, those with below average looks have expected earnings that are ~18% less than those with average looks • Also in specification (3), abvavg = –0.013 (0.033) o Interpretation? 48 Economics 420 (sections 2 and 3) Professor Woodbury Fall Semester 2019 Problem Set #4 (Due:Thursday, November 14) Instructions • • • Use Stata and a word processor for this assignment. Read the question and answer what is asked. For each question that asks you to use Stata, copy and paste the Stata output into a wordprocessing document, then type your answer. Staple all pages together at the upper-left corner before you turn in your homework. • • • Assignments turned in unstapled will be returned with a grade of zero. Only stapling is acceptable—paper clips and other methods of binding are not acceptable. If we cannot discern the meaning of your work, your response will be scored as incorrect. This problem covers three topics: models with a quadratic specification, regression with dummy variables and interaction terms; and hypothesis tests involving multiple parameters. Use the Stata file BEAUTY.dta to answer all the questions. BEAUTY.dta contains the following variables used by Hamermesh and Biddle (American Economic Review 1994): wage educ exper female black union goodhlth looks hourly wage years of schooling years of workforce experience =1 if female, 0 otherwise =1 if black, 0 otherwise =1 if a union member, 0 otherwise =1 if in good health, 0 otherwise physical attractiveness score ranging from 1 to 5 You will also need to generate a few additional variables from those already in the dataset. Part I: Simple dummy variables and the quadratic specification (25 points total) 1. (5 points) Estimate the simple linear regression model: ln(wage) = β0 + β1female + u Interpret the OLS estimates of the intercept and the coefficient on female. Hint: See the section on “Difference-in-means analysis using dummy variables” in . 2. (10 points) Now estimate the following modified Mincer wage equation: ln(wage) = β0 + β1educ + β2exper + β3exper2 + β4female + β5black + β6union + β7goodhlth +u Is the estimated on expersq statistically significant at the 5% level? How do you know? After how many years of experience does a worker’s ln(wage) reach a maximum? Show how you obtained your answer. 3. (5 points) Interpret the coefficient on the “union” dummy variable in the Mincer equation you just estimated. Be sure to consider statistical significance. 4. (5 points) Interpret the coefficient on the “good health” dummy variable in the Mincer equation you just estimated. Be sure to consider statistical significance. Part 2: Interaction terms (25 points total) 1. (10 points) Consider the following simple regression models of log-earnings: ln(wage) = α0 + α1educ + uf (for men only) ln(wage) = β0 + β1educ + um (for women only) Estimate the two regressions and interpret the parameters on education (α1 and β1).Are these coefficients are statistically significant at a level of 0.01? What is the difference between α1 and β1, and how do you interpret it? Hint:To estimate the models, type in Stata: reg lwage educ if female==0 reg lwage educ if female==1 2. (15 points) Now consider the following regression model: ln(wage) = γ0 + γ1educ + γ2female + γ3educ•female + ub (for both women and men) Estimate this regression and interpret fully the four estimated parameters (γ0, γ1, γ2, and γ3). Which of these estimated coefficients are statistically significant at a significance level of 0.01? Does your estimate γ3 make sense in light of what you found in question 1 about the difference between α1 and β1? Explain. Hints:To estimate this model, first generate the interaction between educ and female, which is the product of variables educ and female.To do this, type: gen educ•female = educ*female Then estimate the regression: reg lwage educ female educ•female Part 3: Dummy variables for multiple-categories (30 points total) BEAUTY.dta includes a variable “looks” indicating a persons’s score on physical attractiveness, as ranked by an interviewer.Attractiveness was coded in five categories: 1 = homely 2 = quite plain 3 = average 4 = good looking 5=strikingly beautiful/handsome The dataset also includes two additional variables that we discussed in class: belavg = 1 if looks = 1 or looks = 2, 0 otherwise abvavg = 1 if looks = 4 or looks = 5, 0 otherwise 2 1. (5 points) Create three interaction terms, one for female interacted with belavg, one for female interacted with looks = 3, and a third for female interacted with abvavg. Hint:All you need to do for this question is type in Stata: belavg*female gen abvavg•female = abvavg*female gen avg = (looks==3) gen belavg•female = gen avg•female = avg*female (Note: Just create these dummies; you don’t need to show anything on your homework.) 2. (10 points) Estimate the following model for ln(wage) and report the estimates: ln(wage) = β0 + β1educ + β2exper + β3exper2 + β4belavg + β5abvavg + β6belavg•female + β7avg•female + β8abvavg•female + u Interpret the estimates of β4, and β5. Hint:The omitted category is men of “average” looks, so the coefficients on belavg and abvavg pertain to men of below and above average looks. 3. (10 points) Interpret the estimates of β6, β7, and β8. Hint:Again, the omitted category is men of “average” looks, so for example, the coefficient on belavg•females tells you something about females of “below average” looks relative to men of average looks. 4. (5 points) What is the wage gap between women of “above average” looks and women of “average” looks? Is the difference statistically significant? Hint: Compare the coefficient on abvavg•female with the coefficient on avg•female.To test for the difference, type: lincom abvavg•female – avg•female

Payment Time Case, economics homework help

Description

 

 

Develop a 700-word report including the following calculations and using the information to determine whether the new billing system has reduced the mean bill payment time:

  • Assuming the standard deviation of the payment times for all payments is 4.2 days, construct a 95% confidence interval estimate to determine whether the new billing system was effective. State the interpretation of 95% confidence interval and state whether or not the billing system was effective.
  • Using the 95% confidence interval, can we be 95% confident that µ ≤ 19.5 days?
  • Using the 99% confidence interval, can we be 99% confident that µ ≤ 19.5 days?
  • If the population mean payment time is 19.5 days, what is the probability of observing a sample mean payment time of 65 invoices less than or equal to 18.1077 days?

Include excel file.

Format your assignment consistent with APA format.

ECO 533 University of Miami Advanced Microeconomic Theory Quiz Questions

ECON 533 & ECON 602 Quiz 2, November 15, 2020 Profesor: Manuel S. Santos Fall 2020 PLEASE SUBMIT BEFORE NOVEMBER 22. PLEASE, DO NOT COMMUNICATE WITH YOUR CLASSMATES. You can answer 5 out of 8 short questions, and 2 problems. Grad students must answer 5 short questions (including VI-VIII), and two problems (including problem 3). If you answer six short questions, then one short question counts as bonus. Same for problem 3. 1. QUESTION I: Can you write down a CES production function? Which parameter determines the (constant) elasticity of substitution? And the labor income share? Which assumptions would you need to make in the evolution of wages and rental rates in order to replicate the declining US labor income share? 2. QUESTION II: Suppose that we have increasing returns to scale. Would the cost function be concave or convex in output? Would the marginal cost be increasing or decreasing? Would the optimization problem be well defined? 3. QUESTION III: In some textbooks we are told that tuitive. How would you explain this? @y @w = @L . @p This looks counterin- 4. QUESTION IV: What does it mean third-degree price discrimination? Would you provide some examples? 5. QUESTION V: Please, discuss. Does it make sense for Zara to have these short selling cycles? How Zara grew into the World’s Largest Retailer. ”When you went to Gucci or Chanel in October, you knew the chances were good that clothes would still be there in February,”BUT ”With Zara, you know that if you don’t buy it, right then and there, within 11 days the entire stock will change. You buy it now or never. And because the prices are so low, you buy it now.” 6. QUESTION VI: Could you write down the first-order condition of the prototypical moral hazard model (hidden e↵ort) as a function of the likelihood ratio? How would you interpret this condition to provide optimal incentives for rewarding e↵ort? 7. QUESTION VII In the adverse selection model discussed in class, we encountered the following condition: ✓L C(0, ✓L ) ✓H C(t̂, ✓L ). Please, explain this condition. Moreover, how does this condition get translated in an insurance market with two types of consumers (the bad type and the good type). Hint: Mas-Colell, 13.D.2. 1 8. QUESTION VIII In our corruption paper, is Equation (5) an IR constraint or an IC constraint? Explain the meaning of this constraint (is it a moral hazard model?). Would you suggest any changes to this constraint? 9. PROBLEM 1: A monopolist (AT &T ) is facing the following demand schedule P = 24 3Q. That is, Q = 0 implies P = 24, then Q = 1 implies P = 21, and Q = 2 implies P = 18, and so one. Fixed costs will be neglected in this analysis. The marginal cost is constant and equal to 6 for every unit produced. Determine: (i) The quantity produced corresponding to the amount of maximum profit. (ii) Equilibrium price if a new competitor, Vodafone, enters the market with a MC =6 under both Cournot and Bertrand Competition. (iii) Equilibrium price if a new competitor, Vodafone, enters the market with a MC=7 under Bertrand Competition. (iv) Equilibrium price if a new competitor, Vodafone, enters the market with a MC=5 under Bertrand Competition. 10. PROBLEM 2: Spotify o↵ers a hassle-free (no-commercials) program. Here, at UM, a professor would be willing to subscribe for a monthly free of $30, and a student would be willing to subscribe for $10. There is a second program in which commercials take ten percent of the time. The company will get one-dollar revenue for running these commercials in all cases. However, the disutility of the commercials to each student would be $2, and to a professor would be $8.00. Assume that half of the population are professors and half are students, and Spotify is committed to serve both markets. A. (Market segmentation) Compute the optimal price(s) for each type in the case that Spotify has access to the UM records and is able to tell who is a professor and a student. B. (Hidden Types). Compute optimal price(s) in the case that Spotify has no access to UM records, and cannot identify types. C. (Hidden Types). Assume linear preferences and linear revenues. An undergrad student from ECO 533 has suggested to Spotify to change the second program so that commercials should take 20 percent of the time. Again redo part B, assuming that in the second program commercials take 20 percent of the time. D. (Hidden Types) Actually, our student goes further and claims to have computed the optimal percentage amount of advertising for the second program under the linearity assumption on preferences and commercial revenues. Following part B, are you able to compute the optimal amount of advertising for Spotify serving UM? 11. PROBLEM 3: This is Mas-Collel, 13.C.6. Let us assume the following condition: pG ⇧ (1 + r) > pB ⇧ (1 + r) > 0. Now, following this problem in the book: (i) Find the level of Ri (i = 1, 2) in a separating equilibrium. (ii) Find the level of R in a pooling equilibrium. 2 (iii) How a separating equilibrium will look like in case that the bank can also o↵er a new contract in which the entrepreneur is required to contribute a fraction x of the one dollar initial outlay. Assume that the entrepreneur can get this money at an interest rate ⇢ slightly higher than r. (Else, assume that the entrepreneur has the cash.) 3 ECON 533 & ECON 602 Quiz 2, November 15, 2020 Profesor: Manuel S. Santos Fall 2020 PLEASE SUBMIT BEFORE NOVEMBER 22. PLEASE, DO NOT COMMUNICATE WITH YOUR CLASSMATES. You can answer 5 out of 8 short questions, and 2 problems. Grad students must answer 5 short questions (including VI-VIII), and two problems (including problem 3). If you answer six short questions, then one short question counts as bonus. Same for problem 3. 1. QUESTION I: Can you write down a CES production function? Which parameter determines the (constant) elasticity of substitution? And the labor income share? Which assumptions would you need to make in the evolution of wages and rental rates in order to replicate the declining US labor income share? 2. QUESTION II: Suppose that we have increasing returns to scale. Would the cost function be concave or convex in output? Would the marginal cost be increasing or decreasing? Would the optimization problem be well defined? 3. QUESTION III: In some textbooks we are told that tuitive. How would you explain this? @y @w = @L . @p This looks counterin- 4. QUESTION IV: What does it mean third-degree price discrimination? Would you provide some examples? 5. QUESTION V: Please, discuss. Does it make sense for Zara to have these short selling cycles? How Zara grew into the World’s Largest Retailer. ”When you went to Gucci or Chanel in October, you knew the chances were good that clothes would still be there in February,”BUT ”With Zara, you know that if you don’t buy it, right then and there, within 11 days the entire stock will change. You buy it now or never. And because the prices are so low, you buy it now.” 6. QUESTION VI: Could you write down the first-order condition of the prototypical moral hazard model (hidden e↵ort) as a function of the likelihood ratio? How would you interpret this condition to provide optimal incentives for rewarding e↵ort? 7. QUESTION VII In the adverse selection model discussed in class, we encountered the following condition: ✓L C(0, ✓L ) ✓H C(t̂, ✓L ). Please, explain this condition. Moreover, how does this condition get translated in an insurance market with two types of consumers (the bad type and the good type). Hint: Mas-Colell, 13.D.2. 1 8. QUESTION VIII In our corruption paper, is Equation (5) an IR constraint or an IC constraint? Explain the meaning of this constraint (is it a moral hazard model?). Would you suggest any changes to this constraint? 9. PROBLEM 1: A monopolist (AT &T ) is facing the following demand schedule P = 24 3Q. That is, Q = 0 implies P = 24, then Q = 1 implies P = 21, and Q = 2 implies P = 18, and so one. Fixed costs will be neglected in this analysis. The marginal cost is constant and equal to 6 for every unit produced. Determine: (i) The quantity produced corresponding to the amount of maximum profit. (ii) Equilibrium price if a new competitor, Vodafone, enters the market with a MC =6 under both Cournot and Bertrand Competition. (iii) Equilibrium price if a new competitor, Vodafone, enters the market with a MC=7 under Bertrand Competition. (iv) Equilibrium price if a new competitor, Vodafone, enters the market with a MC=5 under Bertrand Competition. 10. PROBLEM 2: Spotify o↵ers a hassle-free (no-commercials) program. Here, at UM, a professor would be willing to subscribe for a monthly free of $30, and a student would be willing to subscribe for $10. There is a second program in which commercials take ten percent of the time. The company will get one-dollar revenue for running these commercials in all cases. However, the disutility of the commercials to each student would be $2, and to a professor would be $8.00. Assume that half of the population are professors and half are students, and Spotify is committed to serve both markets. A. (Market segmentation) Compute the optimal price(s) for each type in the case that Spotify has access to the UM records and is able to tell who is a professor and a student. B. (Hidden Types). Compute optimal price(s) in the case that Spotify has no access to UM records, and cannot identify types. C. (Hidden Types). Assume linear preferences and linear revenues. An undergrad student from ECO 533 has suggested to Spotify to change the second program so that commercials should take 20 percent of the time. Again redo part B, assuming that in the second program commercials take 20 percent of the time. D. (Hidden Types) Actually, our student goes further and claims to have computed the optimal percentage amount of advertising for the second program under the linearity assumption on preferences and commercial revenues. Following part B, are you able to compute the optimal amount of advertising for Spotify serving UM? 11. PROBLEM 3: This is Mas-Collel, 13.C.6. Let us assume the following condition: pG ⇧ (1 + r) > pB ⇧ (1 + r) > 0. Now, following this problem in the book: (i) Find the level of Ri (i = 1, 2) in a separating equilibrium. (ii) Find the level of R in a pooling equilibrium. 2 (iii) How a separating equilibrium will look like in case that the bank can also o↵er a new contract in which the entrepreneur is required to contribute a fraction x of the one dollar initial outlay. Assume that the entrepreneur can get this money at an interest rate ⇢ slightly higher than r. (Else, assume that the entrepreneur has the cash.) 3 QUIZ 2 Question 2: 1. Increasing returns to scale infers that the cost function is Convex. 2. The marginal cost is increasing. 3. The optimization problem will be defined that variable factor like labor is not fully utilized in increasing returns to scale. Question 4: Third degree price discrimination occurs when a company charges different prices to different groups of consumers. For example, theatres divide their costumers into seniors, adults, and children, and charge them different prices for the same movie. Question 5: Zara makes money by having these short selling cycles. It also helps Zara to clear out all its stock. Luxuries like Gucci and Chanel takes time to clear out their stock. We do not see Gucci and Chanel put “BIG SALE “mark on their windows. And because the price of Zara is lower than Gucci and Chanel, they are easier to clear out stock. This is due to the downward sloping demand curve; Customers will buy things when the price of a product is low. And when the price of a product is high, their willingness to buy will decrease. In this case, prices of luxuries like Gucci and Chanel are high, so the quantity demand for their product is respectively low. Zara, however, set its price respectively low, so the quantity demanded is high. Hence, Zara grew into the world’s largest retailer. MICROECONOMIC THEORY Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Microeconomic Theory Basic Principles and Extensions ELEVENTH EDITION WALTER NICHOLSON Amherst College CHRISTOPHER SNYDER Dartmouth College Australia • Brazil • Japan • Korea • Mexico • Singapore • Spain • United Kingdom • United States Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. This is an electronic version of the print textbook. Due to electronic rights restrictions, some third party content may be suppressed. Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. The publisher reserves the right to remove content from this title at any time if subsequent rights restrictions require it. For valuable information on pricing, previous editions, changes to current editions, and alternate formats, please visit www.cengage.com/highered to search by ISBN#, author, title, or keyword for materials in your areas of interest. Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Microeconomic Theory: Basic Principles and Extensions, Eleventh Edition Walter Nicholson, Christopher Snyder VP/Editorial Director: Jack W. Calhoun Publisher: Joe Sabatino Sr. Acquisitions Editor: Steve Scoble Sr. Developmental Editor: Susanna C. Smart Marketing Manager: Nathan Anderson Sr. Content Project Manager: Cliff Kallemeyn Media Editor: Sharon Morgan Sr. Frontlist Buyer: Kevin Kluck Sr. Marketing Communications Manager: Sarah Greber ª 2012, 2008 South-Western, Cengage Learning ALL RIGHTS RESERVED. No part of this work covered by the copyright herein may be reproduced, transmitted, stored, or used in any form or by any means graphic, electronic, or mechanical, including but not limited to photocopying, recording, scanning, digitizing, taping, web distribution, information networks, or information storage and retrieval systems, except as permitted under Section 107 or 108 of the 1976 United States Copyright Act, without the prior written permission of the publisher. For product information and technology assistance, contact us at Cengage Learning Customer & Sales Support, 1-800-354-9706 For permission to use material from this text or product, submit all requests online at www.cengage.com/permissions Further permissions questions can be emailed to permissionrequest@cengage.com Sr. Rights Specialist: Deanna Ettinger Production Service: Cenveo Publisher Services Sr. Art Director: Michelle Kunkler Internal Designer: Juli Cook/Plan-It Publishing Cover Designer: Red Hangar Design LLC Library of Congress Control Number: 2011928483 ISBN-13: 978-111-1-52553-8 ISBN-10: 1-111-52553-6 Cover Image: ª Jason Reed/Getty Images South-Western 5191 Natorp Boulevard Mason, OH 45040 USA Cengage Learning products are represented in Canada by Nelson Education, Ltd. For your course and learning solutions, visit www.cengage.com Purchase any of our products at your local college store or at our preferred online store www.cengagebrain.com All graphs and figures owned by Cengage Learning. ª 2010 Cengage Learning. Printed in the United States of America 1 2 3 4 5 6 7 15 14 13 12 11 Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. To Beth, Sarah, David, Sophia, Abby, Nate, and Christopher To Maura Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. About the authors Walter Nicholson is the Ward H. Patton Professor of Economics at Amherst College. He received a B.A. in mathematics from Williams College and a Ph.D. in economics from the Massachusetts Institute of Technology (MIT). Professor Nicholson’s primary research interests are in the econometric analyses of labor market problems, including welfare, unemployment, and the impact of international trade. For many years, he has been Senior Fellow at Mathematica, Inc. and has served as an advisor to the U.S. and Canadian governments. He and his wife, Susan, live in Naples, Florida, and Amherst, Massachusetts. Christopher M. Snyder is a Professor of Economics at Dartmouth College. He received his B.A. in economics and mathematics from Fordham University and his Ph.D. in economics from MIT. He is Research Associate in the National Bureau of Economic Research, a member of the Industrial Organization Society board, and Associate Editor of the International Journal of Industrial Organization and Review of Industrial Organization. His research covers various theoretical and empirical topics in industrial organization, contract theory, and law and economics. Professor Snyder and his wife Maura Doyle (who also teaches economics at Dartmouth) live within walking distance of campus in Hanover, New Hampshire, with their three school-aged daughters. Professors Nicholson and Snyder are also the authors of Intermediate Microeconomics and Its Application (Cengage Learning, 2010). vii Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Brief Contents Preface PART ONE xix Introduction CHAPTER 1 CHAPTER 2 PART TWO CHAPTER 4 CHAPTER 5 CHAPTER 6 THREE CHAPTER 8 PART CHAPTER 10 CHAPTER 11 PART CHAPTER 13 SIX CHAPTER 15 PART CHAPTER 17 EIGHT The Partial Equilibrium Competitive Model General Equilibrium and Welfare 457 Monopoly 501 Imperfect Competition Pricing in Input Markets CHAPTER 16 PART Production Functions 303 Cost Functions 333 Profit Maximization 371 409 Market Power 499 CHAPTER 14 SEVEN 301 Competitive Markets 407 CHAPTER 12 PART Uncertainty 209 Game Theory 251 Production and Supply CHAPTER 9 FIVE Preferences and Utility 89 Utility Maximization and Choice 117 Income and Substitution Effects 145 Demand Relationships among Goods 187 Uncertainty and Strategy 207 CHAPTER 7 FOUR 21 Choice and Demand 87 CHAPTER 3 PART 1 Economic Models 3 Mathematics for Microeconomics CHAPTER 19 579 Labor Markets 581 Capital and Time 607 Market Failure CHAPTER 18 531 639 Asymmetric Information 641 Externalities and Public Goods 685 Brief Answers to Queries 717 Solutions to Odd-Numbered Problems 727 Glossary of Frequently Used Terms 739 Index 747 ix Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Contents Preface ……………………………………………………………………………………………………………………………… xix PART ONE Introduction CHAPTER 1 Economic Models …………………………………………………………………………………………………….. 3 Theoretical Models 3 Verification of Economic Models 4 General Features of Economic Models 5 Development of the Economic Theory of Value 9 Modern Developments 17 Summary 18 Suggestions for Further Reading 19 CHAPTER 2 Mathematics for Microeconomics………………………………………………………………………….. 21 Maximization of a Function of One Variable 21 Functions of Several Variables 26 Maximization of Functions of Several Variables 33 The Envelope Theorem 35 Constrained Maximization 39 Envelope Theorem in Constrained Maximization Problems 45 Inequality Constraints 46 Second-Order Conditions and Curvature 48 Homogeneous Functions 55 Integration 58 Dynamic Optimization 63 Mathematical Statistics 67 Summary 76 Problems 77 Suggestions for Further Reading 82 Extensions: Second-Order Conditions and Matrix Algebra 83 PART TWO Choice and Demand CHAPTER 3 Preferences and Utility…………………………………………………………………………………………… 89 Axioms of Rational Choice 89 xi Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. xii Contents Utility 90 Trades and Substitution 92 The Mathematics of Indifference Curves 99 Utility Functions for Specific Preferences 102 The Many-Good Case 106 Summary 106 Problems 107 Suggestions for Further Reading 110 Extensions: Special Preferences 112 CHAPTER 4 Utility Maximization and Choice…………………………………………………………………………… 117 An Initial Survey 118 The Two-Good Case: A Graphical Analysis 119 The n-Good Case 122 Indirect Utility Function 128 The Lump Sum Principle 129 Expenditure Minimization 131 Properties of Expenditure Functions 134 Summary 136 Problems 136 Suggestions for Further Reading 140 Extensions: Budget Shares 141 CHAPTER 5 Income and Substitution Effects …………………………………………………………………………… 145 Demand Functions 145 Changes in Income 147 Changes in a Good’s Price 149 The Individual’s Demand Curve 152 Compensated (Hicksian) Demand Curves and Functions 155 A Mathematical Development of Response to Price Changes 160 Demand Elasticities 163 Consumer Surplus 169 Revealed Preference and the Substitution Effect 174 Summary 176 Problems 177 Suggestions for Further Reading 180 Extensions: Demand Concepts and the Evaluation of Price Indices 181 CHAPTER 6 Demand Relationships among Goods……………………………………………………………………. 187 The Two-Good Case 187 Substitutes and Complements 189 Net (Hicksian) Substitutes and Complements 191 Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Contents xiii Substitutability with Many Goods 193 Composite Commodities 193 Home Production, Attributes of Goods, and Implicit Prices 197 Summary 200 Problems 200 Suggestions for Further Reading 203 Extensions: Simplifying Demand and Two-Stage Budgeting 204 PART THREE Uncertainty and Strategy CHAPTER 7 Uncertainty …………………………………………………………………………………………………………… 209 Mathematical Statistics 209 Fair Gambles and the Expected Utility Hypothesis 210 Expected Utility 211 The von Neumann–Morgenstern Theorem 212 Risk Aversion 214 Measuring Risk Aversion 217 Methods for Reducing Uncertainty and Risk 222 Insurance 222 Diversification 223 Flexibility 224 Information 231 The State-Preference Approach to Choice Under Uncertainty 232 Asymmetry of Information 238 Summary 238 Problems 239 Suggestions for Further Reading 242 Extensions: The Portfolio Problem 244 CHAPTER 8 Game Theory ………………………………………………………………………………………………………… 251 Basic Concepts 251 Prisoners’ Dilemma 252 Nash Equilibrium 254 Mixed Strategies 260 Existence of Equilibrium 265 Continuum of Actions 265 Sequential Games 268 Repeated Games 274 Incomplete Information 277 Simultaneous Bayesian Games 278 Signaling Games 282 Experimental Games 288 Copyright 2011 Cengage Learning. 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Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. xiv Contents Evolutionary Games and Learning 290 Summary 290 Problems 291 Suggestions for Further Reading 295 Extensions: Existence of Nash Equilibrium PART FOUR 296 Production and Supply CHAPTER 9 Production Functions ……………………………………………………………………………………………. 303 Marginal Productivity 303 Isoquant Maps and the Rate of Technical Substitution 306 Returns to Scale 310 The Elasticity of Substitution 313 Four Simple Production Functions 316 Technical Progress 320 Summary 324 Problems 325 Suggestions for Further Reading 328 Extensions: Many-Input Production Functions 329 CHAPTER 10 Cost Functions………………………………………………………………………………………………………. 333 Definitions of Costs 333 Cost-Minimizing Input Choices 336 Cost Functions 341 Cost Functions and Shifts in Cost Curves 345 Shephard’s Lemma and the Elasticity of Substitution 355 Short-Run, Long-Run Distinction 355 Summary 362 Problems 363 Suggestions for Further Reading 366 Extensions: The Translog Cost Function 367 CHAPTER 11 Profit Maximization ………………………………………………………………………………………………. 371 The Nature and Behavior of Firms 371 Profit Maximization 373 Marginal Revenue 375 Short-Run Supply by a Price-Taking Firm 380 Profit Functions 383 Profit Maximization and Input Demand 389 Summary 395 Problems 396 Suggestions for Further Reading 400 Extensions: Boundaries of the Firm 401 Copyright 2011 Cengage Learning. 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Contents PART FIVE xv Competitive Markets CHAPTER 12 The Partial Equilibrium Competitive Model ………………………………………………………….. 409 Market Demand 409 Timing of the Supply Response 413 Pricing in the Very Short Run 413 Short-Run Price Determination 415 Shifts in Supply and Demand Curves: A Graphical Analysis 419 Mathematical Model of Market Equilibrium 422 Long-Run Analysis 425 Long-Run Equilibrium: Constant Cost Case 426 Shape of the Long-Run Supply Curve 428 Long-Run Elasticity of Supply 431 Comparative Statics Analysis of Long-Run Equilibrium 431 Producer Surplus in the Long Run 435 Economic Efficiency and Welfare Analysis 438 Price Controls and Shortages 441 Tax Incidence Analysis 442 Summary 447 Problems 447 Suggestions for Further Reading 451 Extensions: Demand Aggregation and Estimation 453 CHAPTER 13 General Equilibrium and Welfare …………………………………………………………………………. 457 Perfectly Competitive Price System 457 A Graphical Model of General Equilibrium with Two Goods 458 Comparative Statics Analysis 467 General Equilibrium Modeling and Factor Prices 469 A Mathematical Model of Exchange 471 A Mathematical Model of Production and Exchange 482 Computable General Equilibrium Models 485 Summary 489 Problems 490 Suggestions for Further Reading 494 Extensions: Computable General Equilibrium Models 495 PART SIX Market Power CHAPTER 14 Monopoly ……………………………………………………………………………………………………………… 501 Barriers to Entry 501 Copyright 2011 Cengage Learning. 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Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. xvi Contents Profit Maximization and Output Choice 503 Monopoly and Resource Allocation 507 Monopoly, Product Quality, and Durability 510 Price Discrimination 513 Second-Degree Price Discrimination through Price Schedules Regulation of Monopoly 519 Dynamic Views of Monopoly 523 Summary 523 Problems 524 Suggestions for Further Reading 527 Extensions: Optimal Linear Two-Part Tariffs 528 CHAPTER 517 15 Imperfect Competition ………………………………………………………………………………………….. 531 Short-Run Decisions: Pricing and Output 531 Bertrand Model 533 Cournot Model 534 Capacity Constraints 540 Product Differentiation 541 Tacit Collusion 547 Longer-Run Decisions: Investment, Entry, and Exit 551 Strategic Entry Deterrence 557 Signaling 559 How Many Firms Enter? 562 Innovation 566 Summary 568 Problems 569 Suggestions for Further Reading 572 Extensions: Strategic Substitutes and Complements 573 PART SEVEN Pricing in Input Markets CHAPTER 16 Labor Markets ………………………………………………………………………………………………………. 581 Allocation of Time 581 A Mathematical Analysis of Labor Supply 584 Market Supply Curve for Labor 588 Labor Market Equilibrium 589 Wage Variation 591 Monopsony in the Labor Market 595 Labor Unions 598 Summary 601 Problems 601 Suggestions for Further Reading 605 Copyright 2011 Cengage Learning. 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Contents CHAPTER xvii 17 Capital and Time ………………………………………………………………………………………………….. 607 Capital and the Rate of Return 607 Determining the Rate of Return 609 The Firm’s Demand for Capital 616 Present Discounted Value Approach to Investment Decisions 618 Natural Resource Pricing 623 Summary 626 Problems 626 Suggestions for Further Reading 630 APPENDIX The Mathematics of Compound Interest ……………………………………………………………….. 631 Present Discounted Value 631 Continuous Time 633 PART EIGHT Market Failure CHAPTER 18 Asymmetric Information ……………………………………………………………………………………….. 641 Complex Contracts as a Response to Asymmetric Information 641 Principal-Agent Model 642 Hidden Actions 645 Owner-Manager Relationship 646 Moral Hazard in Insurance 650 Hidden Types 655 Nonlinear Pricing 656 Adverse Selection in Insurance 663 Market Signaling 670 Auctions 672 Summary 676 Problems 676 Suggestions for Further Reading 679 Extensions: Nonlinear Pricing with a Continuum of Types 680 CHAPTER 19 Externalities and Public Goods…………………………………………………………………………….. 685 Defining Externalities 685 Externalities and Allocative Inefficiency 687 Solutions to the Externality Problem 691 Attributes of Public Goods 694 Public Goods and Resource Allocation 696 Lindahl Pricing of Public Goods 700 Voting and Resource Allocation 703 A Simple Political Model 705 Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. xviii Contents Voting Mechanisms 708 Summary 710 Problems 710 Suggestions for Further Reading 713 Extensions: Pollution Abatement 714 Brief Answers to Queries…………………………………………………………………………………………………717 Solutions to Odd-Numbered Problems ……………………………………………………………………………727 Glossary of Frequently Used Terms ………………………………………………………………………………… 739 Index ………………………………………………………………………………………………………………………………… 747 Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Preface The 11th edition of Microeconomic Theory: Basic Principles and Extensions continues a successful collaboration between the authors starting with the 10th edition. This edition represents a significant effort to continue refining and modernizing our treatment of microeconomics. Despite the significant changes appearing in virtually every chapter, the text retains all of the elements that have made it successful for so many editions. The basic approach is to focus on building intuition about economic models while providing students with the mathematical tools needed to go further in their studies. The text also seeks to facilitate that linkage by providing many numerical examples, advanced problems, and extended discussions of empirical implementation—all of which are intended to show students how microeconomic theory is used today. New developments continue to keep the field exciting, and we hope this edition manages to capture that excitement. New to the Eleventh Edition We took a fresh look at every chapter to make sure that they continue to provide clear and up-to-date coverage of all of the topics examined. The major revisions include the following. • • • • • • • • • • Many of the topics in our introductory chapter on mathematics have been revised to conform more closely to methods usually encountered in the recent economics literature. The chapters on uncertainty and game theory have been broken out into their own separate part. This shrinks the part of the book on choice and demand to a more manageable size and emphasizes the unique nature of the strategy and uncertainty topics. The chapter on uncertainty (Chapter 7) has been extensively revised. The sections on real options and the value of information have been expanded. Applications to financial economics and the portfolio problem have been streamlined and collected in the Extensions. The treatment of game theory (Chapter 8) has been substantially streamlined, providing the same level of rigor in a third less space. A modern treatment of the literature on firms’ boundaries and objectives (The Theory of the Firm) has been added to the body of Chapter 9 and expanded on further in the Extensions. Our general equilibrium chapter (Chapter 13) has been thoroughly revised. Most notably we now use this chapter to provide students with an elementary introduction to vector notation. We have added a number of new topics to our discussion of labor markets focusing mainly on issues related to human capital and job search. Coverage of behavioral economics has been expanded, sprinkled throughout various relevant chapters. A handful of behavioral economics problems have been included. The public-good problem is rigorously analyzed using game theory (Chapter 19). Dozens of new problems have been added. xix Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. xx Preface Supplements to the Text The thoroughly revised ancillaries for this edition include the following. • • The Solutions Manual and Test Bank (by the text authors). The Solutions Manual contains comments and solutions to all problems, and the test bank has been revised to include additional questions. Both are available to all adopting instructors in electronic version on the text Web site (www.cengage.com/economics/nicholson) and on the Instructor Resources CD (IRCD). PowerPoint Lecture Presentation Slides. PowerPoint slides for each chapter of the text provide a thorough set of outlines for classroom use or for students as a study aid. The slides are available from the book’s Web site (www.cengage.com/economics/ nicholson) and on the IRCD. Online Resources South-Western, a part of Cengage Learning, provides students and instructors with a set of valuable online resources that are an effective complement to this text. Each new copy of the book comes with a registration card that provides access to Economic Applications and InfoTrac College Edition. Economic Applications The purchase of this new textbook includes complimentary access to South-Western’s InfoApps (InfoTrac and Economic Applications) Web site. The Web site includes a suite of regularly updated Web features for economics students and instructors: EconNews, EconDebates, and EconData. These resources can help students deepen their understanding of economic concepts by analyzing current news stories, policy debates, and economic data. EconApps can also help instructors develop assignments, case studies, and examples based on real-world issues. EconDebates provides current coverage of economics policy debates; it includes a primer on the issues, links to background information, and commentaries. EconNews summarizes recent economics news stories and offers questions for further discussion. EconData presents current and historical economic data with accompanying commentary, analysis, and exercises. Students buying a used book can purchase access to InfoApps at www.cengagebrain.com. InfoTrac College Edition The purchase of this new textbook also comes with four months of access to InfoTrac. This powerful and searchable online database provides access to full text articles from more than a thousand different publications ranging from the popular press to scholarly journals. Instructors can search topics and select readings for students, and students can search articles and readings for homework assignments and projects. The publications cover a variety of topics and include articles that range from current events to theoretical developments. InfoTrac College Edition offers instructors and students the ability to integrate scholarship and applications of economics into the learning process. Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Preface xxi Acknowledgments We are indebted to the team at Cengage and especially to Susan Smart for once again bringing her organizing and cajoling skills to this edition. The copyeditors at Cenveo Publisher Services did a great job of making sense of our messy manuscripts. Juli Cook’s text design succeeded in achieving two seemingly irreconcilable goals—making the text both compact and easy to read. Cliff Kallemeyn did a fine job of keeping the production on track; we especially appreciated the way he coordinated the copyediting and page production processes. Devanand Srinivasan supervised the actual production of pages, dealing expertly with the super-abundance of equations. We thank our colleagues at Amherst and Dartmouth College for valuable conversations and understanding. Several colleagues who used the book for their courses offered us detailed suggestions for revision. We have also benefitted from the reactions of generations of students to the use of the book in our own microeconomics classes. Over the years, Amherst students Mark Bruni, Eric Budish, Adrian Dillon, David Macoy, Tatyana Mamut, Anoop Menon, Katie Merrill, Jordan Milev, Doug Norton, and Jeff Rodman and Dartmouth students Wills Begor and Glynnis Kearny worked with us revising various chapters. Walter gives special thanks to his wife Susan; after providing much-needed support through twenty-two editions of his microeconomics texts, she is happy for the success, but wonders about his sanity. Walter’s children (Kate, David, Tory, and Paul) still seem to be living happy and productive lives despite a severe lack of microeconomic education. Perhaps this can be remedied as the next generation (Beth, Sarah, David, Sophia, Abby, Nate, and Christopher) grows older. At least he hopes they will wonder what the books dedicated to them are all about. The texts sit on a convenient shelf, awaiting this curiosity. Chris gives special thanks to his family—his wife, Maura Doyle, and their daughters, Clare, Tess, and Meg—for their patience during the revision process. Maura has extensive experience using the book in her popular microeconomics courses at Dartmouth College, and was a rich source of suggestions reflected in this revision. Perhaps our greatest debt is to instructors who adopt the text, who share a similar view of how microeconomics should be taught. We are grateful for the suggestions that teachers and students have shared with us over the years and encourage teachers and students to continue to e-mail us with any comments on the text (wenicholson@amherst.edu or Christopher.M.Snyder@dartmouth.edu). Walter Nicholson Amherst, Massachusetts Christopher Snyder Hanover New Hampshire July 2011 Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Introduction PART ONE Chapter 1 Economic Models Chapter 2 Mathematics for Microeconomics This part contains two chapters. Chapter 1 examines the general philosophy of how economists build models of economic behavior. Chapter 2 then reviews some of the mathematical tools used in the construction of these models. The mathematical tools from Chapter 2 will be used throughout the remainder of this book. 1 Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. CHAPTER ONE Economic Models The main goal of this book is to introduce you to the most important models that economists use to explain the behavior of consumers, firms, and markets. These models are central to the study of all areas of economics. Therefore, it is essential to understand both the need for such models and the basic framework used to develop them. The goal of this chapter is to begin this process by outlining some of the conceptual issues that determine the ways in which economists study practically every question that interests them. Theoretical Models A modern economy is a complicated entity. Thousands of firms engage in producing millions of different goods. Many millions of people work in all sorts of occupations and make decisions about which of these goods to buy. Let’s use peanuts as an example. Peanuts must be harvested at the right time and shipped to processors who turn them into peanut butter, peanut oil, peanut brittle, and numerous other peanut delicacies. These processors, in turn, must make certain that their products arrive at thousands of retail outlets in the proper quantities to meet demand. Because it would be impossible to describe the features of even these peanut markets in complete detail, economists have chosen to abstract from the complexities of the real world and develop rather simple models that capture the ‘‘essentials.’’ Just as a road map is helpful even though it does not record every house or every store, economic models of, say, the market for peanuts are also useful even though they do not record every minute feature of the peanut economy. In this book we will study the most widely used economic models. We will see that, even though these models often make heroic abstractions from the complexities of the real world, they nonetheless capture essential features that are common to all economic activities. The use of models is widespread in the physical and social sciences. In physics, the notion of a ‘‘perfect’’ vacuum or an ‘‘ideal’’ gas is an abstraction that permits scientists to study real-world phenomena in simplified settings. In chemistry, the idea of an atom or a molecule is actually a simplified model of the structure of matter. Architects use mock-up models to plan buildings. Television repairers refer to wiring diagrams to locate problems. Economists’ models perform similar functions. They provide simplified portraits of the way individuals make decisions, the way firms behave, and the way in which these two groups interact to establish markets. 3 Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 4 Part 1: Introduction Verification of Economic Models Of course, not all models prove to be ‘‘good.’’ For example, the earth-centered model of planetary motion devised by Ptolemy was eventually discarded because it proved incapable of accurately explaining how the planets move around the sun. An important purpose of scientific investigation is to sort out the ‘‘bad’’ models from the ‘‘good.’’ Two general methods have been used for verifying economic models: (1) a direct approach, which seeks to establish the validity of the basic assumptions on which a model is based; and (2) an indirect approach, which attempts to confirm validity by showing that a simplified model correctly predicts real-world events. To illustrate the basic differences between the two approaches, let’s briefly examine a model that we will use extensively in later chapters of this book—the model of a firm that seeks to maximize profits. The profit-maximization model The model of a firm seeking to maximize profits is obviously a simplification of reality. It ignores the personal motivations of the firm’s managers and does not consider conflicts among them. It assumes that profits are the only relevant goal of the firm; other possible goals, such as obtaining power or prestige, are treated as unimportant. The model also assumes that the firm has sufficient information about its costs and the nature of the market to which it sells to discover its profit-maximizing options. Most real-world firms, of course, do not have this information readily available. Yet such shortcomings in the model are not necessarily serious. No model can exactly describe reality. The real question is whether this simple model has any claim to being a good one. Testing assumptions One test of the model of a profit-maximizing firm investigates its basic assumption: Do firms really seek maximum profits? Some economists have examined this question by sending questionnaires to executives, asking them to specify the goals they pursue. The results of such studies have been varied. Businesspeople often mention goals other than profits or claim they only do ‘‘the best they can’’ to increase profits given their limited information. On the other hand, most respondents also mention a strong ‘‘interest’’ in profits and express the view that profit maximization is an appropriate goal. Therefore, testing the profit-maximizing model by testing its assumptions has provided inconclusive results. Testing predictions Some economists, most notably Milton Friedman, deny that a model can be tested by inquiring into the ‘‘reality’’ of its assumptions.1 They argue that all theoretical models are based on ‘‘unrealistic’’ assumptions; the very nature of theorizing demands that we make certain abstractions. These economists conclude that the only way to determine the validity of a model is to see whether it is capable of predicting and explaining real-world events. The ultimate test of an economic model comes when it is confronted with data from the economy itself. Friedman provides an important illustration of that principle. He asks what kind of theory one should use to explain the shots expert pool players will make. He argues that the laws of velocity, momentum, and angles from theoretical physics would be a suitable 1 See M. Friedman, Essays in Positive Economics (Chicago: University of Chicago Press, 1953), chap. 1. For an alternative view stressing the importance of using ‘‘realistic’’ assumptions, see H. A. Simon, ‘‘Rational Decision Making in Business Organizations,’’ American Economic Review 69, no. 4 (September 1979): 493–513. Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Chapter 1: Economic Models 5 model. Pool players shoot shots as if they follow these laws. But most players asked whether they precisely understand the physical principles behind the game of pool will undoubtedly answer that they do not. Nonetheless, Friedman argues, the physical laws provide accurate predictions and therefore should be accepted as appropriate theoretical models of how experts play pool. Thus, a test of the profit-maximization model would be provided by predicting the behavior of real-world firms by assuming that these firms behave as if they were maximizing profits. (See Example 1.1 later in this chapter.) If these predictions are reasonably in accord with reality, we may accept the profit-maximization hypothesis. However, we would reject the model if real-world data seem inconsistent with it. Hence the ultimate test of any theory is its ability to predict real-world events. Importance of empirical analysis The primary concern of this book is the construction of theoretical models. But the goal of such models is always to learn something about the real world. Although the inclusion of a lengthy set of applied examples would needlessly expand an already bulky book,2 the Extensions included at the end of many chapters are intended to provide a transition between the theory presented here and the ways that theory is applied in empirical studies. General Features of Economic Models The number of economic models in current use is, of course, large. Specific assumptions used and the degree of detail provided vary greatly depending on the problem being addressed. The models used to explain the overall level of economic activity in the United States, for example, must be considerably more aggregated and complex than those that seek to interpret the pricing of Arizona strawberries. Despite this variety, practically all economic models incorporate three common elements: (1) the ceteris paribus (other things the same) assumption; (2) the supposition that economic decisionmakers seek to optimize something; and (3) a careful distinction between ‘‘positive’’ and ‘‘normative’’ questions. Because we will encounter these elements throughout this book, it may be helpful at the outset to describe the philosophy behind each of them. The ceteris paribus assumption As in most sciences, models used in economics attempt to portray relatively simple relationships. A model of the market for wheat, for example, might seek to explain wheat prices with a small number of quantifiable variables, such as wages of farmworkers, rainfall, and consumer incomes. This parsimony in model specification permits the study of wheat pricing in a simplified setting in which it is possible to understand how the specific forces operate. Although any researcher will recognize that many ‘‘outside’’ forces (e.g., presence of wheat diseases, changes in the prices of fertilizers or of tractors, or shifts in consumer attitudes about eating bread) affect the price of wheat, these other forces are held constant in the construction of the model. It is important to recognize that economists are not assuming that other factors do not affect wheat prices; rather, such other variables are assumed to be unchanged during the period of study. In this way, the effect 2 For an intermediate-level text containing an extensive set of real-world applications, see W. Nicholson and C. Snyder, Intermediate Microeconomics and Its Application, 11th ed. (Mason, OH: Thomson/Southwestern, 2010). Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 6 Part 1: Introduction of only a few forces can be studied in a simplified setting. Such ceteris paribus (other things equal) assumptions are used in all economic modeling. Use of the ceteris paribus assumption does pose some difficulties for the verification of economic models from real-world data. In other sciences, the problems may not be so severe because of the ability to conduct controlled experiments. For example, a physicist who wishes to test a model of the force of gravity probably would not do so by dropping objects from the Empire State Building. Experiments conducted in that way would be subject to too many extraneous forces (e.g., wind currents, particles in the air, variations in temperature) to permit a precise test of the theory. Rather, the physicist would conduct experiments in a laboratory, using a partial vacuum in which most other forces could be controlled or eliminated. In this way, the theory could be verified in a simple setting, without considering all the other forces that affect falling bodies in the real world. With a few notable exceptions, economists have not been able to conduct controlled experiments to test their models. Instead, they have been forced to rely on various statistical methods to control for other forces when testing their theories. Although these statistical methods are as valid in principle as the controlled experiment methods used by other scientists, in practice they raise a number of thorny issues. For that reason, the limitations and precise meaning of the ceteris paribus assumption in economics are subject to greater controversy than in the laboratory sciences. Structure of Economic Models Most of the economic models you will encounter in this book will have a mathematical structure. They will highlight the relationships between factors that affect the decisions of households and firms and the results of those decisions. Economists tend to use different names for these two types of factors (or, in mathematical terms, variables). Variables that are outside of a decision-maker’s control are called exogenous variables. Such variables are inputs into economic models. For example, in consumer theory we will usually treat individuals as price-takers. The prices of goods are determined outside of our models of consumer behavior, and we wish to study how consumers adjust to them. The results of such decisions (e.g., the quantities of each good that a consumer buys) are endogenous variables. These variables are determined within our models. This distinction is pictured schematically in Figure 1.1. Although the actual models developed by economists may be complicated, they all have this basic structure. A good way to start studying a particular model is to identify precisely how it fits into this framework. This distinction between exogenous and endogenous variables will become clearer as we explore a variety of economic models. Keeping straight which variables are determined outside a particular model and which variables are determined within a model can be confusing; therefore, we will try to remind you about this as we go along. The distinction between exogenous and endogenous variables is also helpful in understanding the way in which the ceteris paribus assumption is incorporated into economic models. In most cases we will want to study how the results of our models change when one of the exogenous variables changes. It is possible, even likely, that the change in such a single variable will change all the results calculated from the model. For example, as we will see, it is likely that the change in the price of a single good will cause an individual to change the quantities of practically every good he or she buys. Examining all such responses is precisely why economists build models. The ceteris paribus assumption is enforced by changing only one exogenous variable, holding all others constant. If we wish to study the effects of a change in the price of gasoline on a household’s purchases, we change that price in our model, but we do not change the prices of other goods (and in some cases we do not change the individual’s income either). Holding the other prices constant is what is meant by studying the ceteris paribus effect of an increase in the price of gasoline. Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Chapter 1: Economic Models FIGURE 1.1 7 Values for exogenous variables are inputs into most economic models. Model outputs (results) are values for the endogenous variables. Structure of a Typical Microeconomic Model EXOGENOUS VARIABLES Households: Prices of goods Firms: Prices of inputs and output ECONOMIC MODEL Households: Utility maximization Firms: Profit maximization ENDOGENOUS VARIABLES Households: Quantities bought Firms: Output produced, inputs hired Optimization assumptions Many economic models start from the assumption that the economic actors being studied are rationally pursuing some goal. We briefly discussed such an assumption when investigating the notion of firms maximizing profits. Example 1.1 shows how that model can be used to make testable predictions. Other examples we will encounter in this book include consumers maximizing their own well-being (utility), firms minimizing costs, and government regulators attempting to maximize public welfare. Although, as we will show, all these assumptions are unrealistic, and all have won widespread acceptance as good starting places for developing economic models. There seem to be two reasons for this acceptance. First, the optimization assumptions are useful for generating precise, solvable models, primarily because such models can draw on a variety of mathematical techniques suitable for optimization problems. Many of these techniques, together with the logic behind them, are reviewed in Chapter 2. A second reason for the popularity of optimization models concerns their apparent empirical validity. As some of our Extensions show, such models seem to be fairly good at explaining reality. In all, then, optimization models have come to occupy a prominent position in modern economic theory. EXAMPLE 1.1 Profit Maximization The profit-maximization hypothesis provides a good illustration of how optimization assumptions can be used to generate empirically testable propositions about economic behavior. Suppose that a firm can sell all the output that it wishes at a price of p per unit and that the total costs of production, C, depend on the amount produced, q. Then profits are given by profits ¼ p ¼ pq  CðqÞ: (1:1) Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 8 Part 1: Introduction Maximization of profits consists of finding that value of q which maximizes the profit expression in Equation 1.1. This is a simple problem in calculus. Differentiation of Equation 1.1 and setting that derivative equal to 0 give the following first-order condition for a maximum: dp ¼ p  C 0 ðqÞ ¼ 0 or dq p ¼ C 0 ðqÞ: (1:2) In words, the profit-maximizing output level (q) is found by selecting that output level for which price is equal to marginal cost, C 0 ðqÞ. This result should be familiar to you from your introductory economics course. Notice that in this derivation the price for the firm’s output is treated as a constant because the firm is a price-taker. That is, price is an exogenous variable in this model. Equation 1.2 is only the first-order condition for a maximum. Taking account of the secondorder condition can help us to derive a testable implication of this model. The second-order condition for a maximum is that at q it must be the case that d 2p ¼ C 00 ðqÞ < 0 dq 2 or C 00 ðq Þ > 0: (1:3) That is, marginal cost must be increasing at q for this to be a true point of maximum profits. Our model can now be used to ‘‘predict’’ how a firm will react to a change in price. To do so, we differentiate Equation 1.2 with respect to price (p), assuming that the firm continues to choose a profit-maximizing level of q: d½ p  C 0 ðq Þ ¼ 0 dq ¼ 0: ¼ 1  C 00 ðq Þ  dp dp (1:4) Rearranging terms a bit gives dq 1 ¼ 00  > 0: dp C ðq Þ (1:5) Here the final inequality again reflects the fact that marginal cost must be increasing at q if this point is to be a true maximum. This then is one of the testable propositions of the profitmaximization hypothesis—if other things do not change, a price-taking firm should respond to an increase in price by increasing output. On the other hand, if firms respond to increases in price by reducing output, there must be something wrong with our model. Although this is a simple model, it reflects the way we will proceed throughout much of this book. Specifically, the fact that the primary implication of the model is derived by calculus, and consists of showing what sign a derivative should have, is the kind of result we will see many times. Notice that in this model there is only one endogenous variable—q, the quantity the firm chooses to produce. There is also only one exogenous variable—p, the price of the product, which the firm takes as a given. Our model makes a specific prediction about how changes in this exogenous variable affect the firm’s output choice. QUERY: In general terms, how would the implications of this model be changed if the price a firm obtains for its output were a function of how much it sold? That is, how would the model work if the price-taking assumption were abandoned? Positive-normative distinction A final feature of most economic models is the attempt to differentiate carefully between ‘‘positive’’ and ‘‘normative’’ questions. Thus far we have been concerned primarily with positive economic theories. Such theories take the real world as an object to be studied, attempting to explain those economic phenomena that are observed. Positive economics seeks to determine how resources are in fact allocated in an economy. A somewhat different use of economic theory is normative analysis, taking a definite stance about what should be done. Under the heading of normative analysis, economists have a great deal to Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Chapter 1: Economic Models 9 say about how resources should be allocated. For example, an economist engaged in positive analysis might investigate how prices are determined in the U.S. health-care economy. The economist also might want to measure the costs and benefits of devoting even more resources to health care by, for example, offering government-subsidized health insurance. But when he or she specifically advocates that such an insurance plan should be adopted, the analysis becomes normative. Some economists believe that the only proper economic analysis is positive analysis. Drawing an analogy with the physical sciences, they argue that ‘‘scientific’’ economics should concern itself only with the description (and possibly prediction) of real-world economic events. To take political positions and to plead for special interests are considered to be outside the competence of an economist acting as such. Of course, an economist, like any other citizen, is free to express his or her views on political matters. But when doing so he or she is acting as a citizen, not an economist. For other economists, however, the positive-normative distinction seems artificial. They believe that the study of economics necessarily involves the researchers’ own views about ethics, morality, and fairness. According to these economists, searching for scientific ‘‘objectivity’’ in such circumstances is hopeless. Despite some ambiguity, this book tries to adopt a positivist tone, leaving normative concerns for you to decide for yourself. Development of the Economic Theory of Value Because economic activity has been a central feature of all societies, it is surprising that these activities were not studied in any detail until fairly recently. For the most part, economic phenomena were treated as a basic aspect of human behavior that was not sufficiently interesting to deserve specific attention. It is, of course, true that individuals have always studied economic activities with a view toward making some kind of personal gain. Roman traders were not above making profits on their transactions. But investigations into the basic nature of these activities did not begin in any depth until the eighteenth century.3 Because this book is about economic theory as it stands today, rather than the history of economic thought, our discussion of the evolution of economic theory will be brief. Only one area of economic study will be examined in its historical setting: the theory of value. Early economic thoughts on value The theory of value, not surprisingly, concerns the determinants of the ‘‘value’’ of a commodity. This subject is at the center of modern microeconomic theory and is closely intertwined with the fundamental economic problem of allocating scarce resources to alternative uses. The logical place to start is with a definition of the word ‘‘value.’’ Unfortunately, the meaning of this term has not been consistent throughout the development of the subject. Today we regard value as being synonymous with the price of a commodity.4 Earlier philosopher-economists, however, made a distinction between the market price of a commodity and its value. The term value was then thought of as being, in some sense, synonymous with ‘‘importance,’’ ‘‘essentiality,’’ or (at times) ‘‘godliness.’’ Because ‘‘price’’ and ‘‘value’’ were separate concepts, they could differ, and most early economic 3 For a detailed treatment of early economic thought, see the classic work by J. A. Schumpeter, History of Economic Analysis (New York: Oxford University Press, 1954), pt. II, chaps. 1–3. 4 This is not completely true when ‘‘externalities’’ are involved, and a distinction must be made between private and social value (see Chapter 19). Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 10 Part 1: Introduction discussions centered on these divergences. For example, St. Thomas Aquinas believed value to be divinely determined. Because prices were set by humans, it was possible for the price of a commodity to differ from its value. A person accused of charging a price in excess of a good’s value was guilty of charging an ‘‘unjust’’ price. St. Thomas believed that, in most cases, the ‘‘just’’ rate of interest was zero. Any lender who demanded a payment for the use of money was charging an unjust price and could be—and sometimes was—prosecuted by church officials. The founding of modern economics During the latter part of the eighteenth century, philosophers began to take a more scientific approach to economic questions. The 1776 publication of The Wealth of Nations by Adam Smith (1723–1790) is generally considered the beginning of modern economics. In his vast, all-encompassing work, Smith laid the foundation for thinking about market forces in an ordered and systematic way. Still, Smith and his immediate successors, such as David Ricardo (1772–1823), continued to distinguish between value and price. To Smith, for example, the value of a commodity meant its ‘‘value in use,’’ whereas the price represented its ‘‘value in exchange.’’ The distinction between these two concepts was illustrated by the famous water–diamond paradox. Water, which obviously has great value in use, has little value in exchange (it has a low price); diamonds are of little practical use but have a great value in exchange. The paradox with which early economists struggled derives from the observation that some useful items have low prices whereas certain nonessential items have high prices. Labor theory of exchange value Neither Smith nor Ricardo ever satisfactorily resolved the water–diamond paradox. The concept of value in use was left for philosophers to debate, while economists turned their attention to explaining the determinants of value in exchange (i.e., to explaining relative prices). One obvious possible explanation is that exchange values of goods are determined by what it costs to produce them. Costs of production are primarily influenced by labor costs—at least this was so in the time of Smith and Ricardo—and therefore it was a short step to embrace a labor theory of value. For example, to paraphrase an example from Smith, if catching a deer takes twice the number of labor hours as catching a beaver, then one deer should exchange for two beavers. In other words, the price of a deer should be twice that of a beaver. Similarly, diamonds are relatively costly because their production requires substantial labor input, whereas water is freely available. To students with even a passing knowledge of what we now call the law of supply and demand, Smith’s and Ricardo’s explanation must seem incomplete. Did they not recognize the effects of demand on price? The answer to this question is both yes and no. They did observe periods of rapidly rising and falling relative prices and attributed such changes to demand shifts. However, they regarded these changes as abnormalities that produced only a temporary divergence of market price from labor value. Because they had not really developed a theory of value in use, they were unwilling to assign demand any more than a transient role in determining relative prices. Rather, long-run exchange values were assumed to be determined solely by labor costs of production. The marginalist revolution Between 1850 and 1880, economists became increasingly aware that to construct an adequate alternative to the labor theory of value, they had to devise a theory of value in use. During the 1870s, several economists discovered that it is not the total usefulness of a commodity that helps to determine its exchange value, but rather the usefulness of the last unit consumed. For example, water is certainly useful—it is necessary for all life. Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Chapter 1: Economic Models 11 Marshall theorized that demand and supply interact to determine the equilibrium price (p) and the quantity (q) that will be traded in the market. He concluded that it is not possible to say that either demand or supply alone determines price or therefore that either costs or usefulness to buyers alone determines exchange value. FIGURE 1.2 The Marshallian Supply–Demand Cross Price D S p* D S q* Quantity per period However, because water is relatively plentiful, consuming one more pint (ceteris paribus) has a relatively low value to people. These ‘‘marginalists’’ redefined the concept of value in use from an idea of overall usefulness to one of marginal, or incremental, usefulness— the usefulness of an additional unit of a commodity. The concept of the demand for an incremental unit of output was now contrasted with Smith’s and Ricardo’s analysis of production costs to derive a comprehensive picture of price determination.5 Marshallian supply–demand synthesis The clearest statement of these marginal principles was presented by the English economist Alfred Marshall (1842–1924) in his Principles of Economics, published in 1890. Marshall showed that demand and supply simultaneously operate to determine price. As Marshall noted, just as you cannot tell which blade of a scissors does the cutting, so too you cannot say that either demand or supply alone determines price. That analysis is illustrated by the famous Marshallian cross shown in Figure 1.2. In the diagram the quantity of a good purchased per period is shown on the horizontal axis, and its price appears on the vertical axis. The curve DD represents the quantity of the good demanded per period at each possible price. The curve is negatively sloped to reflect the marginalist principle that as quantity increases, people are willing to pay less for the last unit purchased. It is the value of this last unit that sets the price for all units purchased. The curve SS shows how (marginal) production costs increase as more output is produced. This reflects the increasing cost of producing one more unit as total output expands. In other words, the upward slope of the SS curve reflects increasing marginal costs, just as the downward slope of the DD curve reflects decreasing marginal value. The two curves intersect at p, q. This is an equilibrium point—both buyers and sellers are content with the quantity being traded and the price at which it is traded. If one of the curves should shift, the equilibrium point would shift to a new location. Thus, price and quantity are simultaneously determined by the joint operation of supply and demand. 5 Ricardo had earlier provided an important first step in marginal analysis in his discussion of rent. Ricardo theorized that as the production of corn increased, land of inferior quality would be used and this would cause the price of corn to increase. In his argument Ricardo recognized that it is the marginal cost—the cost of producing an additional unit—that is relevant to pricing. Notice that Ricardo implicitly held other inputs constant when discussing decreasing land productivity; that is, he used one version of the ceteris paribus assumption. Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 12 Part 1: Introduction EXAMPLE 1.2 Supply–Demand Equilibrium Although graphical presentations are adequate for some purposes, economists often use algebraic representations of their models both to clarify their arguments and to make them more precise. As an elementary example, suppose we wished to study the market for peanuts and, based on the statistical analysis of historical data, concluded that the quantity of peanuts demanded each week (q, measured in bushels) depended on the price of peanuts (p, measured in dollars per bushel) according to the equation: quantity demanded ¼ qD ¼ 1,000  100p: (1:6) Because this equation for qD contains only the single independent variable p, we are implicitly holding constant all other factors that might affect the demand for peanuts. Equation 1.6 indicates that, if other things do not change, at a price of $5 per bushel people will demand 500 bushels of peanuts, whereas at a price of $4 per bushel they will demand 600 bushels. The negative coefficient for p in Equation 1.6 reflects the marginalist principle that a lower price will cause people to buy more peanuts. To complete this simple model of pricing, suppose that the quantity of peanuts supplied also depends on price: quantity supplied ¼ qS ¼ 125 þ 125p: (1:7) Here the positive coefficient of price also reflects the marginal principle that a higher price will call forth increased supply—primarily because (as we saw in Example 1.1) it permits firms to incur higher marginal costs of production without incurring losses on the additional units produced. Equilibrium price determination. Therefore, Equations 1.6 and 1.7 reflect our model of price determination in the market for peanuts. An equilibrium price can be found by setting quantity demanded equal to quantity supplied: qD ¼ qS (1:8) 1,000  100p ¼ 125 þ 125p (1:9) 225p ¼ 1,125 (1:10) p ¼ 5: (1:11) or or thus, At a price of $5 per bushel, this market is in equilibrium: At this price people want to purchase 500 bushels, and that is exactly what peanut producers are willing to supply. This equilibrium is pictured graphically as the intersection of D and S in Figure 1.3. A more general model. To illustrate how this supply–demand model might be used, let’s adopt a more general notation. Suppose now that the demand and supply functions are given by qD ¼ a þ bp and qS ¼ c þ dp (1:12) where a and c are constants that can be used to shift the demand and supply curves, respectively, and b (0) represent demanders’ and suppliers’ reactions to price. Equilibrium in this market requires qD ¼ qS or a þ bp ¼ c þ dp: (1:13) Thus, equilibrium price is given by6 p ¼ ac : db (1:14) 6 Equation 1.14 is sometimes called the ‘‘reduced form’’ for the supply–demand structural model of Equations 1.12 and 1.13. It shows that the equilibrium value for the endogenous variable p ultimately depends only on the exogenous factors in the model (a and c) and on the behavioral parameters b and d. A similar equation can be calculated for equilibrium quantity. Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Chapter 1: Economic Models 13 FIGURE 1.31Changing Supply–Demand Equilibria The initial supply–demand equilibrium is illustrated by the intersection of D and S (p ¼ 5, q ¼ 500). When demand shifts to qD 0 ¼ 1; 450  100p ðdenoted as D 0 Þ, the equilibrium shifts to p ¼ 7, q ¼ 750. Price ($) D′ 14.5 S D 10 7 5 S 0 500 750 D D′ 1,000 1,450 Quantity per period (bushels) Notice that in our previous example a ¼ 1,000, b ¼ 100, c ¼ 125, and d ¼ 125; therefore, p ¼ 1,000 þ 125 1,125 ¼ ¼ 5: 125 þ 100 225 (1:15) With this more general formulation, however, we can pose questions about how the equilibrium price might change if either the demand or supply curve shifted. For example, differentiation of Equation 1.14 shows that dp 1 ¼ > 0; da db  dp 1 ¼ < 0: dc db (1:16) That is, an increase in demand (an increase in a) increases equilibrium price, whereas an increase in supply (an increase in c) reduces price. This is exactly what a graphical analysis of supply and demand curves would show. For example, Figure 1.3 shows that when the constant term, a, in the demand equation increases to 1,450, equilibrium price increases to p ¼ 7 [¼ (1,450 þ 125)/225]. QUERY: How might you use Equation 1.16 to ‘‘predict’’ how each unit increase in the exogenous constant a affects the endogenous variable p? Does this equation correctly predict the increase in p when the constant a increases from 1,000 to 1,450? Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 14 Part 1: Introduction Paradox resolved Marshall’s model resolves the water–diamond paradox. Prices reflect both the marginal evaluation that demanders place on goods and the marginal costs of producing the goods. Viewed in this way, there is no paradox. Water is low in price because it has both a low marginal value and a low marginal cost of production. On the other hand, diamonds are high in price because they have both a high marginal value (because people are willing to pay quite a bit for one more) and a high marginal cost of production. This basic model of supply and demand lies behind much of the analysis presented in this book. General equilibrium models Although the Marshallian model is an extremely useful and versatile tool, it is a partial equilibrium model, looking at only one market at a time. For some questions, this narrowing of perspective gives valuable insights and analytical simplicity. For other, broader questions, such a narrow viewpoint may prevent the discovery of important relationships among markets. To answer more general questions we must have a model of the whole economy that suitably mirrors the connections among various markets and economic agents. The French economist Leon Walras (1831–1910), building on a long Continental tradition in such analysis, created the basis for modern investigations into those broad questions. His method of representing the economy by a large number of simultaneous equations forms the basis for understanding the interrelationships implicit in general equilibrium analysis. Walras recognized that one cannot talk about a single market in isolation; what is needed is a model that permits the effects of a change in one market to be followed through other markets. For example, suppose that the demand for peanuts were to increase. This would cause the price of peanuts to increase. Marshallian analysis would seek to understand the size of this increase by looking at conditions of supply and demand in the peanut market. General equilibrium analysis would look not only at that market but also at repercussions in other markets. An increase in the price of peanuts would increase costs for peanut butter makers, which would, in turn, affect the supply curve for peanut butter. Similarly, the increasing price of peanuts might mean higher land prices for peanut farmers, which would affect the demand curves for all products that they buy. The demand curves for automobiles, furniture, and trips to Europe would all shift out, and that might create additional incomes for the providers of those products. Consequently, the effects of the initial increase in demand for peanuts eventually would spread throughout the economy. General equilibrium analysis attempts to develop models that permit us to examine such effects in a simplified setting. Several models of this type are described in Chapter 13. Production possibility frontier Here we briefly introduce some general equilibrium ideas by using another graph you should remember from introductory economics—the production possibility frontier. This graph shows the various amounts of two goods that an economy can produce using its available resources during some period (say, one week). Because the production possibility frontier shows two goods, rather than the single good in Marshall’s model, it is used as a basic building block for general equilibrium models. Figure 1.4 shows the production possibility frontier for two goods: food and clothing. The graph illustrates the supply of these goods by showing the combinations that can be produced with this economy’s resources. For example, 10 pounds of food and 3 units of clothing could be produced, or 4 pounds of food and 12 units of clothing. Many other combinations of food and clothing could also be produced. The production possibility frontier shows all of them. Combinations of food and clothing outside the frontier cannot Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. Chapter 1: Economic Models FIGURE 1.4 Production Possibility Frontier 15 The production possibility frontier shows the different combinations of two goods that can be produced from a certain amount of scarce resources. It also shows the opportunity cost of producing more of one good as the amount of the other good that cannot then be produced. The opportunity cost at two different levels of clothing production can be seen by comparing points A and B. Quantity of food per week Opportunity cost of clothing = 12 pound of food A 10 9.5 Opportunity cost of clothing = 2 pounds of food B 4 2 0 3 4 12 13 Quantity of clothing per week be produced because not enough resources are available. The production possibility frontier reminds us of the basic economic fact that resources are scarce—there are not enough resources available to produce all we might want of every good. This scarcity means that we must choose how much of each good to produce. Figure 1.4 makes clear that each choice has its costs. For example, if this economy produces 10 pounds of food and 3 units of clothing at point A, producing 1 more unit of clothing would ‘‘cost’’ ½ pound of food—increasing the output of clothing by 1 unit means the production of food would have to decrease by ½ pound. Thus, the opportunity cost of 1 unit of clothing at point A is ½ pound of food. On the other hand, if the economy initially produces 4 pounds of food and 12 units of clothing at point B, it would cost 2 pounds of food to produce 1 more unit of clothing. The opportunity cost of 1 more unit of clothing at point B has increased to 2 pounds of food. Because more units of clothing are produced at point B than at point A, both Ricardo’s and Marshall’s ideas of increasing incremental costs suggest that the opportunity cost of an additional unit of clothing will be higher at point B than at point A. This effect is shown by Figure 1.4. The production possibility frontier provides two general equilibrium insights that are not clear in Marshall’s supply and demand model of a single market. First, the graph shows that producing more of one good means producing less of another good because resources are scarce. Economists often (perhaps too often!) use the expression ‘‘there is no such thing as a free lunch’’ to explain that every economic action has opportunity costs. Second, the production possibility frontier shows that opportunity costs depend on how much of each good is produced. The frontier is like a supply curve for two goods: It Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 16 Part 1: Introduction shows the opportunity cost of producing more of one good as the decrease in the amount of the second good. Therefore, the production possibility frontier is a particularly useful tool for studying several markets at the same time. EXAMPLE 1.3 The Production Possibility Frontier and Economic Inefficiency General equilibrium models are good tools for evaluating the efficiency of various economic arrangements. As we will see in Chapter 13, such models have been used to assess a wide variety of policies such as trade agreements, tax structures, and environmental regulations. In this simple example, we explore the idea of efficiency in its most elementary form. Suppose that an economy produces two goods, x and y, using labor as the only input. The production function for good x is x ¼ lx0:5 (where lx is the quantity of labor used in x production), and the production function for good y is y ¼ 2ly0:5 . Total labor available is constrained by lx þ ly  200. Construction of the production possibility frontier in this economy is extremely simple: lx þ ly ¼ x2 þ 0:25y2  200 (1:17) where the equality holds exactly if the economy is to be producing as much as possible (which, after all, is why it is called a ‘‘frontier’’). Equation 1.17 shows that the frontier here has the shape of a quarter ellipse—its concavity derives from the diminishing returns exhibited by each production function. Opportunity cost. Assuming this economy is on the frontier, the opportunity cost of good y in terms of good x can be derived by solving for y as pffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi (1:18) y2 ¼ 800  4×2 or y ¼ 800  4×2 ¼ ½800  4×2 0:5 And then differentiating this expression: dy 4x ¼ 0:5½800  4×2 0:5 ð8xÞ ¼ : dx y (1:19) Suppose, for example, labor is equally allocated between the two goods. Then x ¼ 10, y ¼ 20, and dy/dx ¼ 4(10)/20 ¼ 2. With this allocation of labor, each unit increase in x output would require a reduction in y of 2 units. This can be verified by considering a slightly different allocation, lx ¼ 101 and ly ¼ 99. Now production is x ¼ 10.05 and y ¼ 19.9. Moving to this alternative allocation would have Dy ð19:9  20Þ 0:1 ¼ ¼ ¼ 2, Dx ð10:05  10Þ 0:05 which is precisely what was derived from the calculus approach. Concavity. Equation 1.19 clearly illustrates the concavity of the production possibility frontier. The slope of the frontier becomes steeper (more negative) as x output increases and y output decreas

Week 2 hw Benefit-Cost Analysis of Dam Construction Projects

Description

 

 

Corporations have to select among many projects that are under consideration by the management. Their

primary instrument for evaluating and selecting among the available projects is the benefit-cost analysis. In

this analysis, both the annual benefits and the annual costs deriving from a project are estimated in several

different categories. Then the total benefit is divided by the total cost to produce a benefit-cost ratio. This

ratio is then used by corporations to compare numerous projects under consideration. A benefit-cost

ratio greater than 1.0 indicates that the benefits are greater than the costs, and the higher a project’s

benefit-cost ratio, the more likely it is to be selected over projects with lower ratios.

Currently, the JET Corporation is evaluating two dam project constructions, one in southwest Georgia

(Dam #1) and the other in North Carolina (Dam #2). The company has identified six areas of benefits:

improved navigation, hydroelectric power, fish and wildlife, recreation, flood control, and the commercial

development of the area. Furthermore, there are three estimates available for each type benefit – a

minimum possible value, a most likely value (i.e., a mode or peak), and a maximum possible value. For the

costs, two categories associated with a construction project of this type have been identified: the total

capital cost, annualized over 30 years (at a rate specified by the creditors and the government), and the

annual operations and maintenance costs. These benefits and costs estimations for both dam projects (in

millions of dollars) are as follows:

 

5 Short Answer Questions

Description

 

 

21.

In an essay of at least two well-developed paragraphs, explain the global benefits of international trade and multinational corporations.

22.

In complete sentence format, explain (a) two of the three types of trade barriers, (b) the reasons why countries sometimes establish trade barriers, and (c) the effects trade barriers sometimes have on the economy.

23.

In an essay of at least two well-developed paragraphs, analyze four of the factors that can affect economic development in some countries.

24.

In an essay of at least two well-developed paragraphs, explain why countries enter into free trade agreements. Provide the names of three trade agreements you have studied in this unit, and provide a brief description of each.

25.

In an essay of at least three well-developed paragraphs, (a) explain one economic difficulty for people traveling and conducting business between countries, and (b) describe the two exchange rate systems and how they function in alleviating these problems.

PRG/420: Java Programming – 8 LABS

 

(LAB 8) Two smallest numbers

 

 

 

Write a program that reads a list of integers, and outputs the two smallest integers in the list, in ascending order. The input begins with an integer indicating the number of integers that follow. You can assume that the list will have at least 2 integers and fewer than 20 integers.

 

Ex: If the input is:

 

5 10 5 3 21 2

 

the output is:

 

2 3

 

To achieve the above, first read the integers into an array.

 

Hint: Make sure to initialize the second smallest and smallest integers properly.

 

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LAB1OutputNumbers.png

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LAB2MiddleItem.png

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LAB4AdjustList.png

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LAB3OutoutValuesBelow.png

attachment

LAB5WordFrequencies.png

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LAB6ContainstheCharact

four types of perceptual distortions

Discusses four types of perceptual distortions: stereotyping, halo effects, selective perception, and projection. Define each of these types of perceptual distortions and provide a full example of each perceptual distortion.

For each discussion, you are required to write an initial post (300 words) and one secondary post (200 words).  The discussion forums will be worth 40 points apiece—25 points for the initial post and 15 points for the secondary post.  For your initial and secondary posts, you must have two academic peer-reviewed articles for references.  You must get them from the library.  There are directions at the top of our Moodle page showing how to utilize the library

Reply to below response

 

Types of perceptual distortions:

Perception is the way toward incorporating their condition. In layman’s words, it is a half-production procedure to understand their environment to react legitimately. The current condition of the perceptual beneficiary depends on the brain, character and appreciation, where there is dependably a blunder in the depiction and ensuing data.

Stereotyping:

Stereotyping is specific gathering or class (social, ethnic, religious, or sexual introductions) just based on enrollment of the property, for example, he is an Italian, so he knows a ton about Rome. The most widely recognized, the adjustment in the obstruction

Halo effect:

Halo effect is between the two, a steady paying little respect to the general population is a component of the innovation depends on the numerous highlights Bust constructive effect on the great quality, have an antagonistic effect of terrible element in the purposes behind the other party less experienced individual, a notable attributes of the solid good ramifications For example, he is chuckling, so he should come clean.

Selective Perception:

Selective perception is the alternative Awareness Support and trust in the data that affirms the conviction that the pre-channel that depicts the particular data.

Projection:

Projection that they have the properties themselves or hand over to others emotions. For example, I have a few things that I experience the ill effects of it will put off, to defer our gathering can state an example he says.

visual analysis

demonstrate the ability to utilize persuasive appeals (logos, pathos, and ethos), argument strategies, and writing techniques similar to professional models of argumentative writing to analysis a visual image (film—Shadow of a Doubt). The student chooses one of the visual elements (color, texture, line, space, forms, shapes, and/or value) and one of the film elements (narrative, cinematography, sound, mise-en-scene, or editing) to interpret/analyze the film posted on e-campus and to show how these elements create a rhetorical appeal/response (ethos, logos, pathos, or kairos) to the film. The student uses evidence from at least two sources to support the analysis of the visual and film elements. The student defends his or her stance on the analysis of the visual image to move an audience to action.

Which philosopher would agree most with this statement “Human…

Which philosopher would agree most with this statement “Human…

Which philosopher would agree most with this statement “Human…

Which philosopher would agree most with this statement “Human knowledge

is a collection of information and experiences.”; Kant, Hume, Plato, or Russell? Explain why.