EXAMPLE 14.14 Are the Standard Deviations Equal?

CASE 14.1 Figure 14.10 shows output of the modified Levene’s test for the moral reasoning study. In both JMP and SAS, the test is called Brown-Forsythe. The -value is 0.0377, which is smaller than , suggesting the variances are not the same. This is not that surprising a result given the boxplots in Figure 14.4 (page 716). There, we see that the spread in the scores for the control group is much larger than the spread in the other two groups.