1. The following study is a very famous medical study called the Physicians' Health Study I. It was begun in 1982 and involved 22,071 male physicians between the ages of 40 and 81. One of the goals of the study was to determine if taking 325 mg of aspirin every other day would reduce a man's risk of a first heart attack. This was a randomized clinical trial which means each subject in the study was randomly assigned one of two treatments - taking an aspirin every other day or taking a placebo every other day. About 11,000 subjects were randomly assigned to take an aspirin every other day, and about 11,000 subjects were randomly assigned to take a placebo every other day. The study lasted 5 years. At the end of the study, the researchers described their results by reporting the percentage of heart attacks in the group taking aspirin and in the group taking a placebo. They found 0.9% of the group taking aspirin and 1.7% of the group taking a placebo had heart attacks. They used statistical methods to predict that US men aged 40 or older who take aspirin every other day have a lower risk of having a first heart attack compared to men who don't take an aspirin every other day. Match each term with the aspect of the study to which it refers: Inference, Design, or Description.

A. The sample, the randomization (random assignment of treatment), and the plan to obtain percentages of each group that have heart attacks.

B. The actual percentages of the people in the sample who have heart attacks.

C. The use of statistical methods to make the prediction that US men aged 40 or older who take aspirin every other day have a lower risk of having a first heart attack compared to men who don't take an aspirin every other day.

2. In the previous question describing the study of 22,071 male physicians who were randomly assigned to take either an aspirin or a placebo every other day. Match each of the following terms to its correct description: sample, subject, or population.