Any group representing a factor level or interaction that is tested with the split-plot error term (the split-plot error term is in the denominator of the F-statistic) should have equivalent variances. In addition, the variances of the differences between levels should be equivalent. Formal tests and model adjustments to account for unequal variances are beyond the scope of this text. An individual value plot (or boxplot) showing all factor- level combinations in the split- plot portion of the ANOVA can be used to roughly test for equal variances. For this memory study, create an individual value plot of each test score categorized by major, type of word list, and type of distracter. With such a small sample size in each group, it is very difficult to determine whether any of the Major, Wordlist, or Distracter factor combinations have unequal variances.