ABSTRACT
The between-subjects factorial analysis of variance is one of a number of analysis of variance procedures which are employed to evaluate a factorial design. A hctorial design is employed to simultaneously evaluate the effect of two or more independent variables on a dependent variable. Each of the independent variables is refmed to as a factor. Each of the Mars has two or more levels, which refer to the number of groupslexperimental conditions which comprise that independent variable. If a factorial design is not employed to assess the effect of multiple independent variables on a dependent variable, separate experiments must be conducted to evaluate the effect of each of the independent variables. One major advantage of a hctorial design is that it allows the same set of hypotheses to be evaluated at a comparable level ofpower by using only a fiaction of the subjects that would be required if separate experiments were conducted to evaluate the relevant hypotheses for each of the independent variables. Another advantage of a factorial design is that it permits a researcher to evaluate whether or not there is an interaction between two or more independent variables - something which cannot be determined if only one independent variable is employed in a study. An interaction is present in a set of data when the performance of subjects on one independent variable is not consistent across all the levels of another independent variable. The concept of interaction is discussed in detail in Section V.
