What is an independent variable in an experiment?

In experimental research, an independent variable is the factor that the researcher manipulates to observe its effect on another variable, known as the dependent variable. This manipulation is essential for establishing cause-and-effect relationships. By changing the independent variable, researchers can investigate how this change influences the outcome or behavior being studied.

For example, in an experiment examining the effect of different amounts of sunlight on plant growth, the amount of sunlight is the independent variable. Researchers can intentionally alter the amount of sunlight exposure for different groups of plants to measure its effect on growth, which would be the dependent variable. This clear distinction between the independent variable (the factor being manipulated) and the dependent variable (the outcome or effect being measured) is fundamental to experimental design.

In contrast, a measured and affected factor corresponds to the dependent variable, the constant variable refers to those factors that do not change throughout the experiment, and a measure of the outcome is also related to the dependent variable. Thus, understanding the role of the independent variable as the manipulated factor is crucial for grasping how experiments are structured to test hypotheses.