1. See page 11, first paragraph. What does it mean for “…the difference in means by insurance status [to be] contaminated by selection bias?”

Read Mastering Metrics pages 11 and 12. Answer the following questions.* Please don’t try to answer these questions until you’ve carefully read both pages associated with this week’s assignment. You can either prepare your answers using a word processing program, and upload your answers here in either DOC, DOCX or PDF format, or type your answers directly into the text entry box.

1. See page 11, first paragraph. What does it mean for “…the difference in means by insurance status [to be] contaminated by selection bias?”

2. See page 11, second paragraph. Why do the individuals with insurance in Table 1.1 have higher levels of health than those individuals without health insurance?

3. See page 11, third paragraph. What does it mean for “…the principle challenge facing masters of ’metrics is elimination of the selection bias that arises from … unobserved differences.”

4. See page 12, first paragraph. What does it mean to say, “Experimental random assignment eliminates selection bias.”? In your own words, describe how an experiment with random assignment of subjects into control and treatment groups works to overcome the challenges brought about by unobserved factors that plagued the comparison of health outcomes by insurance status in the survey data in Table 1.1.