Which variable is manipulated or varied in an experiment?

The independent variable is the element of an experiment that is manipulated or varied by the researcher to observe its effects on other variables. This is a fundamental aspect of experimental design, as it allows researchers to establish cause-and-effect relationships. For instance, if a researcher is studying the effect of different amounts of sunlight on plant growth, the amount of sunlight would be the independent variable. By changing the levels of sunlight, the researcher can observe how these changes influence the growth of the plants, which would be the dependent variable.

Understanding the role of the independent variable is crucial in evaluating any research or experimental results, as it provides insight into how specific changes lead to different outcomes. This manipulation enables the researcher to determine if there is a direct relationship between the independent and dependent variables, thereby validating or refuting their hypothesis.