What is an example of an independent variable?

An independent variable is a factor that is manipulated or changed by the researcher in an experiment to observe its effect on a dependent variable. This manipulation is essential for establishing cause-and-effect relationships in research. By altering the independent variable, researchers can assess how these changes influence other variables, known as dependent variables. This concept is fundamental in experimental design because it allows scientists to determine how varying conditions impact outcomes.

In the context of the available choices, the choice indicating that a factor manipulated by the researcher accurately defines an independent variable. It emphasizes the active role of the researcher in shaping the research conditions to explore specific hypotheses or questions. The focus on manipulation distinguishes independent variables from other types of data or conditions that might be observed or controlled within an experiment.