Identify the correct statements regarding variables in an experimental study.…

Concept

In an experimental design, variables are classified by their functional role. The independent variable is deliberately manipulated or selected by the researcher, while the dependent variable is the response that is observed or measured.

Extraneous variables are other influences on the outcome. Researchers try to control relevant extraneous variables when feasible; variables deliberately held constant are control variables, which reduce confounding rather than create spurious relationships.

Application

1. The claim about the independent variable describes its usual role in an experiment, so statement A is true.

2. The dependent variable records the response or outcome, so statement B is true.

3. The word “always” makes statement C too absolute: some extraneous variables may remain uncontrolled or even unidentified.

4. Control variables are held constant to prevent confounding; statement D reverses their purpose and is false.

Cross-check

• Accepting statement C would imply that no uncontrolled extraneous influence can remain, even though such influences are precisely a source of confounding.

• Accepting statement D would treat holding a factor constant as the source of a spurious association, whereas that control is used to reduce such associations.

Therefore, only statements A and B are valid. The answer is “A and B only”.