Independent variable manipulation – UGC NET Question

The independent variable is the one that the researcher systematically changes or manipulates to study its impact on another variable. It is considered the presumed cause in a cause–effect relationship. By varying the independent variable across groups or conditions, the researcher can observe differences in outcomes and infer potential causal effects. Therefore, the manipulated variable described in the stem is the independent variable.

Option A:
The dependent variable is the outcome that is measured to see how it responds to changes in the independent variable. It is not directly manipulated but observed. Because the stem emphasises deliberate manipulation, dependent does not fit.

Option B:
An intervening variable lies in the causal chain between independent and dependent variables and explains the process linking them. It is not usually under direct experimental control in basic designs.

Option C:
Extraneous variables are any uncontrolled factors that may influence the dependent variable and threaten internal validity. Researchers seek to eliminate or control them, but they are not the focus of deliberate manipulation.

Option D:
The independent variable is selected and manipulated according to the research design, such as using different teaching methods or time allocations. Observed differences in the dependent variable across conditions are then attributed, under proper controls, to this independent variable. This matches the description in the stem, making this option correct.