The limits of the external validity of the effects of each of the two independent variables in a complex design are specified when
A)there is no interaction effect of the two variables but significant main effects for both variables.
B)there is no interaction effect of the two variables and neither variable produces a main effect.
C)there is no interaction effect of the two variables and one independent variable has a main effect but the other variable does not.
D)there is an interaction effect of the two variables and main effects of the variables may or may not be present.

Question

Quizplus · Accepted Answer

When there is an interaction effect of the two variables, it means that the effects of each independent variable on the dependent variable differ depending on the level of the other independent variable. This makes it difficult to generalize the effects of each independent variable separately, as their effects are intertwined. Therefore, the limits of external validity in a complex design are specified when there is an interaction effect, regardless of the presence or absence of main effects.

The Limits of the External Validity of the Effects of Each