Which term best describes a variable that is deliberately changed by the researcher to observe its effect on another variable?

Which term best describes a variable that is deliberately changed by the researcher to observe its effect on another variable?

• A. Confounding variable
• B. Dependent variable
• C. Control variable
• D. Independent variable

Answer: (D)

The main idea here is identifying the variable that the researcher actively changes to see its effect. This is chosen or manipulated on purpose to observe what happens to another variable, which is the outcome being measured. In experimental design, that manipulated factor is the independent variable, because it stands apart as the input the study controls. To see how it works in practice, think of studying whether amount of study time influences exam performance. The amount of study time is the independent variable because you decide how many hours to allocate and then observe the effect on the exam score, which is the dependent variable—the outcome you measure. Other variables that might affect the score but aren’t being intentionally changed, like a student’s inherent ability or test anxiety, can confound results if not controlled. A confounding variable is something that unintentionally influences the dependent variable. A control variable is something you hold constant to isolate the effect of the independent variable and avoid alternative explanations.

The main idea here is identifying the variable that the researcher actively changes to see its effect. This is chosen or manipulated on purpose to observe what happens to another variable, which is the outcome being measured. In experimental design, that manipulated factor is the independent variable, because it stands apart as the input the study controls.

To see how it works in practice, think of studying whether amount of study time influences exam performance. The amount of study time is the independent variable because you decide how many hours to allocate and then observe the effect on the exam score, which is the dependent variable—the outcome you measure. Other variables that might affect the score but aren’t being intentionally changed, like a student’s inherent ability or test anxiety, can confound results if not controlled. A confounding variable is something that unintentionally influences the dependent variable. A control variable is something you hold constant to isolate the effect of the independent variable and avoid alternative explanations.