Question

determine whether the study is an experiment or an observational study, and then identify a major problem with the study. the physicians health study involved 22,071 male physicians. based on random selections, 11,037 of them were treated with aspirin and the other 11,034 were given placebos. the study was stopped early because it became clear that aspirin reduced the risk of myocardial infarctions by a substantial amount. this is a dropdown 1 because the researchers dropdown 2 the individuals. what is a major problem? a. this is an observational study with heart disease. b. this is an experiment with physicians. c. this is a convenience sample which has a high chance of leading to bias. d. this is a convenience sample with voluntary response, which has a high chance of leading to bias.

Explanation:

An experiment involves researchers manipulating variables. Here, researchers gave some physicians aspirin and others placebos, which is a form of manipulation. A major problem with such a study could be that the sample consists only of male physicians, which may not be representative of the general population and can lead to bias.

Answer:

This is an experiment because the researchers administered treatments (aspirin or placebo) to the individuals.
What is a major problem? C. The sample consists only of male physicians, which has a high chance of leading to bias.