What is an independent variable in an experiment?

An independent variable in an experiment is the factor that the researcher manipulates or controls to observe its effects on other variables. In experimental research, researchers change or adjust the independent variable to determine if it causes any changes in the dependent variable, which is the outcome they are measuring.

This distinction is crucial because it allows researchers to establish cause-and-effect relationships in their studies. For instance, if a study is examining how different amounts of sunlight affect plant growth, the amount of sunlight would be the independent variable since it is intentionally altered to see how it influences the growth of the plants, which is the dependent variable.

Understanding the role of the independent variable helps clarify how experiments are structured and how findings can be interpreted. In contrast, the other options refer to different components of an experiment, such as the dependent variable, constant factors, and outcomes, which do not accurately describe what an independent variable is.