Which of the following best defines an independent variable in an experiment?

An independent variable is the factor that researchers intentionally manipulate or change in an experiment to observe its effect on another variable, known as the dependent variable. This means that the independent variable is the cause in a cause-and-effect relationship. By varying this variable, scientists can assess how changes impact the outcomes measured in the experiment.

In this context, the definition provided outlines that it is the variable controlled by the experimenter, which allows them to test hypotheses and draw conclusions based on the outcome observed. This makes it essential for experiments aimed at establishing relationships between different variables. The focus is on the relationship and the manipulation of this variable to observe changes in the dependent variable, thereby highlighting its pivotal role in experimental design.