miacervenka
miacervenka
08.10.2020 • 
Mathematics

oes regular exercise reduce the risk of a heart attack? Provided are two ways to study this question. A researcher finds 20002000 men older than age 4040 who exercise regularly and have not had heart attacks. She matches each with a similar man who does not exercise regularly, and she follows both groups for 55 years. Another researcher finds 40004000 men older than age 4040 who have not had heart attacks and are willing to participate in a study. She assigns 20002000 of the men to a regular program of supervised exercise. The other 20002000 continue their usual habits. The researcher follows both groups for 55 years. Select the correct explanation clearly detailing why the second design will produce more trustworthy data.

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