1. Please define a case control study. What are the components of a case control study?

2. Suppose that a case–control study was conducted in the United States to find out whether a Black woman’s exposure to racism during pregnancy influenced her risk of giving birth prematurely. Investigators selected 500 cases who were hospitalized for premature delivery and 1,000 controls. The study found that 90 case mothers and 50 control mothers reported overt incidents of racism during their pregnancy.

A. Set up the two-by-two table for these data.

B. Calculate the odds ratio.

C. State in words your interpretation of this odds ratio.

D. Suppose that the investigators hire you as an epidemiological consultant to help them design this study. They ask you what type of control group is most appropriate for the study. Briefly describe the control group that you would advise them to select, and justify your choice.

E. The investigators also ask you to describe the purpose of the control group in a case–control study. What would you tell them?