Sound levels are measured at random moments under typical driving conditions for various full-size truck models.The ANOVA results are shown below. The test statistic for Hartley's test for homogeneity of variance is
A)2.25
B)5.04
C)4.61
D)4.45

Question

Sound levels are measured at random moments under typical driving conditions for various full-size truck models.The ANOVA results are shown below.   The test statistic for Hartley's test for homogeneity of variance is
A)2.25 
B)5.04 
C)4.61 
D)4.45

Quizplus · Accepted Answer

The test statistic for Hartley's test is calculated by dividing the largest sample variance by the smallest sample variance. Here, the largest variance is 65.1 and the smallest variance is 12.9, so the test statistic is 65.1/12.9 = 5.04. The critical value for Hartley's test with 3 groups and alpha = 0.05 is 3.11. Since 5.04 > 3.11, we reject the null hypothesis of equal variances and conclude that the variances are not homogeneous. Therefore, we should use a modified ANOVA that accounts for unequal variances, such as Welch's ANOVA.

Sound Levels Are Measured at Random Moments Under Typical Driving