What defines the control group in an experimental study?

The control group in an experimental study is essential for establishing a baseline for comparison against the experimental group, which receives the treatment or intervention being tested. The control group does not receive the experimental treatment, allowing researchers to observe the effects of the treatment by comparing outcomes between the two groups.

By having a control group, researchers can isolate the variable being tested and account for other factors that may influence the results. This helps to strengthen the internal validity of the study, as any differences in outcomes between the groups can be attributed to the experimental treatment rather than other external influences.

In contrast, the other options pertain to different aspects of the experimental procedure or population sampling and do not accurately define the role of the control group within the experimental framework.