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.

The second design will produce more trustworthy data because there are equal number of men above the age of 40 grouped into two categories those who exercise and those who do not exercise.

The first design does not produce such accurate results because the two sample sizes may be quite different and the second group may have candidates of any age other than 40.

The null hypothesis for this design will be u ≠ 40 against the alternate hypothesis that u= 40.

This will give a two tailed test.

All the result possibilities will be for both men aged above 40 and below 40 excluding out only the 40 aged men.

In the second design the sample sizes are same and the both samples may have men aged older than 40

The null hypothesis for this design will be u => 40 (Mean is greater and equal to 40) against the claim u < 40 .

This will give a one tailed test.

So this design will give better results.

All the result possibilities will be for men aged above 40.