15.41 Pooling the standard deviations.
Refer to the previous exercise. Here are the standard deviations for attitude toward brand:
| Repetition | |||
| Familiarity | 1 | 2 | 3 |
| Familiar | 1.16 | 1.46 | 1.16 |
| Unfamiliar | 1.39 | 1.22 | 1.42 |
Assuming that the cell sizes are equal, find the pooled estimate of the standard deviation for these data. Use the rule for examining standard deviations in ANOVA from Chapter 14 (page 720) to determine if it is reasonable to use a pooled standard deviation for the analysis of these data.
15.41
Assuming equal cell sizes, It is reasonable to pool the standard deviations because the largest s is less than twice the smallest