The drug finasteride is marketed as Propecia to help protect against male pattern baldness, and it also may protect against prostate cancer. A large sample of healthy men over age 55 were randomly assigned to receive either a daily finasteride pill or a placebo. The study lasted seven years and the men had annual check-ups and a biopsy at the end of the study. Prostate cancer was found in 804 of 4368 men taking finasteride and in 1145 of the 4692 men taking a placebo.

(a) Is this an experiment or an observational study? The study was double-blind; what does that mean?

(b) What are the variables in the study?

(c) Make a two-way table to display the results. Include the row and column totals.

(d) What percent of men in the study received finasteride?

(e) What percent of the men with prostate cancer were in the placebo group?

(f) Compare the percent of men getting prostate cancer between the two groups. Does finasteride appear to offer some protection against prostate cancer?