Date: Oct 4, 1999 4:29 PM Author: Steve Schnick Subject: How to combine the standard deviations of multiple data subsets If one has several subsets of a given data set, and the mean, count,

and standard deviations for each of these subsets, how can one

calculate the combined standard deviation of the data subsets? i.e.,

if the subsets were lumped together into one set, how does one

calculate this new standard deviation?

Thanks.