15.25 Estimating the within-group variance.
Refer to the previous exercise. Here are the cell standard deviations and sample sizes for cooking enjoyment:
| Culture | ||||||
| Canada | United States | France | ||||
| Gender | ||||||
| Female | 1.668 | 238 | 1.736 | 178 | 2.024 | 82 |
| Male | 1.909 | 125 | 1.601 | 101 | 1.875 | 87 |
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.
15.25
, so . It is reasonable to pool the standard deviations because the largest is less than twice the smallest .