What is the purpose of using a control in an experiment?

The purpose of using a control in an experiment is to establish a baseline for comparison. A control serves as a standard against which the results of the experimental group can be measured. By keeping one group under standard conditions, researchers can identify the effects of the independent variable on the dependent variable by comparing the results from the experimental group with those from the control group. This comparison helps to ensure that any observed changes in the experimental group can be attributed specifically to the treatment or condition being tested, rather than to other extraneous factors.

In contrast, creating variability in results can lead to confusion and complicate the interpretation of the data; increasing sample size primarily aims to improve the statistical power of an experiment but does not directly relate to the function of a control; and isolating variables is a technique used in experimental design but does not define the purpose of a control itself.