What defines a confounding variable?

What defines a confounding variable?

• A. A variable that is manipulated to observe effects on the DV.
• B. A variable apart from the IV which can affect the DV. However it can't be controlled.
• C. The baseline measure in a repeated measures design.
• D. The method of random allocation of participants.

Answer: (B)

A confounding variable is any factor other than the manipulated independent variable that can influence the dependent variable. If this extra variable varies in the same way as the IV or differs between groups, it can create a false impression that the IV caused the observed effect. That’s why controlling or randomizing potential confounds is crucial for interpreting results. This choice matches the idea: it describes a variable that is separate from the IV but can affect the DV. In practice, researchers try to control such variables (through random assignment, counterbalancing, or keeping conditions constant) to prevent them from skewing results. For example, if studying two teaching methods on test scores, students’ motivation could be a confounding variable if it’s not balanced across groups; the observed difference might reflect motivation rather than the method itself. The other options describe things that are not confounding variables: a manipulated variable is the IV, a baseline measure in a repeated-measures design is a starting point for comparison, and random allocation is a method used to reduce confounding rather than a variable that confounds.

A confounding variable is any factor other than the manipulated independent variable that can influence the dependent variable. If this extra variable varies in the same way as the IV or differs between groups, it can create a false impression that the IV caused the observed effect. That’s why controlling or randomizing potential confounds is crucial for interpreting results.

This choice matches the idea: it describes a variable that is separate from the IV but can affect the DV. In practice, researchers try to control such variables (through random assignment, counterbalancing, or keeping conditions constant) to prevent them from skewing results. For example, if studying two teaching methods on test scores, students’ motivation could be a confounding variable if it’s not balanced across groups; the observed difference might reflect motivation rather than the method itself.

The other options describe things that are not confounding variables: a manipulated variable is the IV, a baseline measure in a repeated-measures design is a starting point for comparison, and random allocation is a method used to reduce confounding rather than a variable that confounds.