Chapter 4.2, Problem 56E

To determine

To explain why it was necessary to include a control group in this experiment.

Explanation of Solution

In this study, the researchers wants to study that if the testosterone supplements are given then can it reverse some effects on the male body as the age increases or not.

Thus, Netherlands assigned some men aged $60\text{ to }80$ with low or low-normal testosterone levels to either a testosterone supplements or a placebo. The control group is defined as the group in an experiment or study that does not receive treatment by the researchers and is then used as a benchmark to measure how the other tested subjects do. Thus, to examine the result of the experiment two groups are chosen one with testosterone supplements and the other one with a placebo to compare the results of both to find out if testosterone supplements really helps men or not with the effects on the body. Thus, the control group is important for the experiment.