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 an dropdown because the researchers dropdown the individuals. experiment observational study

Explanation:

An experiment involves researchers manipulating variables (giving aspirin or placebo). Here, researchers assigned treatments to the male physicians. A major problem could be that the study was stopped early, which may affect the long - term validity of the results and the generalizability of the findings about the long - term effects of aspirin on reducing the risk of myocardial infarctions.

Answer:

This is an experiment because the researchers administered treatments (aspirin or placebo) to the individuals.
A major problem with the study is that it was stopped early.