# pooled variance is weighted variance where (nx-1) is weightage of first variance?

The pooled variance is an estimate of the common variance. It is a weighted average of the sample variances for each group, where the larger groups are weighted more heavily than smaller groups. that makes pooled variance is weighted average of variance of all the samples. Can you please confirm?

1 answers ( 0 marked as helpful)

That is correct, https://en.wikipedia.org/wiki/Pooled_variance also contains this phrasing. Essentially if we had a population sizes of 8 and 2, then our best estimate of the global variance is by taking a larger contribution of the larger sample