Why is a control group important in an experiment?

A control group is essential in experimental research because it provides a baseline against which the effects of the independent variable can be measured. By having a group that does not receive the treatment or the experimental manipulation, researchers can determine if any changes observed in the experimental group are indeed due to the manipulation of the independent variable rather than other factors. This comparison enables researchers to establish a cause-and-effect relationship and enhances the internal validity of the experiment.

When the control group is included, it serves as a reference point, which helps in identifying whether the results in the experimental group are significant or if they could have occurred due to random chance or pre-existing differences between groups. Thus, the presence of a control group is fundamental for making valid conclusions about the impact of the independent variable on the dependent variable.