What does the term 'independent variable' refer to in an experiment?

The term 'independent variable' refers to the variable that is manipulated or controlled by the researcher in an experiment. This variable is changed to observe how it affects the dependent variable, which is the outcome measured in the experiment. By controlling the independent variable, researchers can determine its causal impact on the dependent variable, allowing for clearer conclusions about the relationships between various factors in the study.

For example, if a researcher is studying the effect of different amounts of sunlight on plant growth, the amount of sunlight is the independent variable that is being altered. The growth of the plants, which will be measured to see how it varies with the sunlight, is the dependent variable.

In contrast, the other options refer to concepts that do not accurately describe the independent variable. The outcome that is measured pertains to the dependent variable, while the constant variable relates to controlled variables that do not change during the experiment to ensure that the experiment’s results are due solely to the manipulation of the independent variable. Lastly, stating that the independent variable has no impact on the dependent variable contradicts its very definition, which is centered on exploring and determining such impacts.