14.43 Pooling variances.
An experiment was run to compare four groups. The sample sizes were 30, 32, 150, and 33, and the corresponding estimated standard deviations were 25, 22, 13, and 23.
14.43
(a) Yes, the largest is less than twice the smallest ; . (b) 625, 484, 169, 529. (c) . (d) . (e) The third group has the largest sample size and will influence or weight the pooled standard deviation more.