In an experiment to test the effect of a new weight loss drug, half of the people in the study received the drug, and the other half received a placebo (a pill that has no physiological effect). In addition, only males from the ages of 20 to 25 were selected to participate in the study. All participants received their treatments (drug or placebo) every day for 4 weeks. Which of the following components of the study design served as the control group?
A) The 4-week length of the experiment.
B) The restriction of study participants in age and gender.
C) The participants who received a placebo.
D) The participants who received the drug.

Question

Quizplus · Accepted Answer

The control group in this experiment is the group of participants who received the placebo, as this group allows for a comparison of the effects of the drug with the effects of no treatment. The other options (A, B, and D) do not serve as control groups. Option A is simply a feature of the design, option B is a restriction that was imposed for the purposes of the study, and option D was the treatment group being tested.

In an Experiment to Test the Effect of a New