CUNY Bronx Community College Plots Percentiles Measures of Center and Spread Lab 9

CUNY Bronx Community College Plots Percentiles Measures of Center and Spread Lab 9

CUNY Bronx Community College Plots Percentiles Measures of Center and Spread Lab 9

 

HW #9 (part) – Plots, Percentiles, Measures of Center, and Spread
Show all work.
1. Sociology: College Graduates
What percentage of the general U.S. population have a bachelor’s degree or higher?
The following data set gives the percentage of college graduates for a sample of 25 U.S. states.
(Source: The Statistical Abstract of the United States, 129th edition, 2010)
17, 26, 35, 34, 19, 19, 48, 26, 26, 23, 19, 23, 20, 24, 27, 26, 24, 35, 34, 22, 30, 30, 25, 31, 26
a) Find the mean, median, and mode.
b) Determine the five number summary.
c) Find the IQR (interquartile range).
d) Draw a box-and-whisker plot.
e) Louisiana has a bachelor’s degree percentage rate of approximately 20% and New Jersey
has a bachelor’s degree percentage rate of approximately 34%. Into which quartile does
each of those percentage rates fall?
f) Are there any potential outliers in this set? Use the IQR method to determine whether or
not there any potential outliers.
g) Compute a 5% trimmed mean.
2. One standard for admission to Redfield College is that the student rank in the upper quartile
of his or her graduating high school class. What is the minimal percentile rank of a successful
applicant?
3. On the NY State Mathematics Assessment, a sixth grader’s score was in the 94th percentile in
their district, but was in the 78th percentile in the state. How does their performance compare to
other students in the district and other students in the state? Why might the percentiles be
different?
4.

5. Given the population data set: {5, 9, 10, 11, 15}
a) Find the mean and standard deviation.
b) Add 5 to each data value. Then, find the mean and standard deviation of the new data set.
c) Compare the two standard deviation values. In general, how does the standard deviation
change when the same constant is added to each data value? Explain.
6.
(c)