test of simple effects
in an analysis of variance, a test used to determine the effect of one independent variable on the dependent variable at a single level of a second independent variable; that is, the test is used to examine the effects of one of the independent variables with the other independent variable held constant. For example, consider a researcher who finds a statistically significant interaction between two independent variables, A and B, that each have two levels, A1 and A2 and B1 and B2. In this case, a test of simple effects involves two statistical tests: one of the difference between A1 and A2 at B1 and a second of the difference between A1 and A2 at B2. The comparisons can also be undertaken by examining the difference between B1 and
B2 at A1 and the difference between B1 and B2 at A2.