In an experiment, the variable whose change is deliberate is called the independent variable; the variable that depends on it is the dependent variable.

• A. The dependent variable is manipulated by the experimenter; the independent variable depends on the dependent
• B. The independent variable is measured after manipulation
• C. The independent variable is changed by the researcher; the dependent variable depends on it
• D. They are both constants

Answer: (C)

The concept being tested is which variable you deliberately change versus which one you observe as a response. In an experiment, you set or alter the independent variable to see what effect it has, and you measure the dependent variable to observe that effect. The best description matches this: the independent variable is changed by the researcher, and the dependent variable depends on it. This captures both the cause-and-effect relationship: the experimenter controls the cause (the independent variable) and the outcome (the dependent variable) is what changes in response.

If the statement said the dependent variable is manipulated, that would misidentify which variable you control. If it suggested the independent variable is just measured after manipulation, it downplays the essential idea that you deliberately change it to study its effect. If both were constants, that would contradict the whole purpose of an experiment.