ANOVA-TWO-WAY-VARIABLES (DV IV1 IV2)
Calculates the analysis of variance when there are two factors that may affect the dependent variable, specifically `iv1' and `iv2.' Unlike the one-way ANOVA, there are mathematical difficulties with the two-way ANOVA if there are unequal cell sizes; therefore, we require all cells to be the same size; that is, the same number of values (of the dependent variable) for each combination of the independent factors. The result of the analysis is an anova-table, as described in the manual. This function differs from `anova-two-way-groups' only in its input representation. See the manual for further discussion of analysis of variance. The row effect is `iv1' and the column effect is `iv2.'