In an experimental study with a treatment group and a no-treatment control group, the control group provides

• A. To act as baseline for comparison
• B. To ensure randomization
• C. To receive the best treatment
• D. To confuse results

Answer: (A)

The main idea is that a control group provides a baseline for comparison to isolate the effect of the treatment. By not receiving the treatment, this group shows what happens in the absence of the intervention, giving a reference point against which the treatment group’s outcomes can be judged. This lets you attribute any differences in results to the treatment itself rather than to natural variation or other factors.

Randomization is about how participants are assigned to groups to keep them comparable; it’s a design feature, not the function of the control group itself. The control group does not receive the best treatment—that would be the treatment group. And a properly designed control helps clarify results rather than confuse them.