The controlled variable whose effects on the response variable we wish to study is called

• A. Primary data
• B. Control group
• C. Respondents
• D. Explanatory variable

Answer: (D)

The main idea here is identifying the factor you deliberately change to see how it influences the outcome you measure. That factor is the explanatory variable (also known as the independent variable). It’s the piece you adjust to observe what happens to the response variable, which is the outcome you’re interested in.

Think of a plant growth study: the amount of fertilizer used is the explanatory variable, because you’re varying it to see how it affects plant height, the response variable. Other factors like sunlight or water would be kept constant to avoid muddying the result; those are controlled variables. A control group would be a baseline comparison, and respondents are the participants providing data.

So the term for the variable whose effects you wish to study is the explanatory variable.