Which variable is manipulated by the investigator?

Which variable is manipulated by the investigator?

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

Answer: (D)

In experimental design, the factor you deliberately change to see its effect is the independent variable. This is the variable the investigator manipulates to observe whether and how the outcome changes. The outcome you measure in response is the dependent variable. To ensure a clear link between the manipulation and the result, other factors are kept constant as control variables. If other, unintended factors creep in, they become confounding variables that can mislead conclusions about the effect of the manipulated variable. So, the element you actively adjust to test cause-and-effect is the independent variable.

In experimental design, the factor you deliberately change to see its effect is the independent variable. This is the variable the investigator manipulates to observe whether and how the outcome changes. The outcome you measure in response is the dependent variable. To ensure a clear link between the manipulation and the result, other factors are kept constant as control variables. If other, unintended factors creep in, they become confounding variables that can mislead conclusions about the effect of the manipulated variable. So, the element you actively adjust to test cause-and-effect is the independent variable.