Which effect occurs when the influence of one factor changes across levels of another factor?

Which effect occurs when the influence of one factor changes across levels of another factor?

• A. Interaction effect
• B. Main effect
• C. Simple effect
• D. Post-hoc effect

Answer: (A)

When one factor’s influence is not the same at all levels of another factor, that is an interaction effect. It means the effect of one variable depends on the level of the other variable. In practice, you’d see this as non-parallel or changing patterns in an interaction plot, or as a significant interaction term in an analysis of variance. For example, if a teaching method helps one age group more than another, the method’s impact isn’t uniform across ages. If you looked only at overall main effects, you’d miss how the factors modify each other.

When one factor’s influence is not the same at all levels of another factor, that is an interaction effect. It means the effect of one variable depends on the level of the other variable. In practice, you’d see this as non-parallel or changing patterns in an interaction plot, or as a significant interaction term in an analysis of variance. For example, if a teaching method helps one age group more than another, the method’s impact isn’t uniform across ages. If you looked only at overall main effects, you’d miss how the factors modify each other.