What is the purpose of using control groups in experiments?

Using control groups in experiments serves the crucial purpose of establishing a baseline for comparison against the experimental group. A control group is not exposed to the experimental treatment or intervention, which allows researchers to observe what happens to the subjects under standard conditions. By comparing results from the experimental group, which does receive the treatment, to those of the control group, researchers can determine whether the observed effects are indeed due to the independent variable being tested. This comparison helps isolate the effect of the treatment and enhances the validity of the findings.

In contrast, manipulating the independent variable, altering the dependent variable, or increasing the sample size are elements that do not specifically convey the essential role that control groups play in experimental design. Control groups focus on maintaining consistent conditions to effectively measure the impact of changes introduced in the experimental group.