In an experiment, what is the purpose of having a control group?

A control group is essential in an experiment because it serves as a baseline for comparison, which allows researchers to determine the effect of the independent variable on the dependent variable. By keeping the control group unchanged, researchers can observe what happens when the independent variable is not applied, providing a reference point against which the effects seen in the experimental group can be measured. This helps to isolate the impact of the independent variable, eliminating alternative explanations for any changes observed.

Having this baseline is crucial for establishing causal relationships and ensuring the reliability of the experiment's findings. It allows researchers to attribute any differences in outcomes directly to the manipulation of the independent variable rather than to other uncontrolled factors.