Tim Churches <tchur@OPTUSHOME.COM.AU> wrote [originally]: > I am having some difficulties reproducing the results calculated by PROC > MEANS for a weighted std error of the mean. I am using the formula > provided in the SAS documentation (see > http://jeff-lab.queensu.ca/stat/sas/sasman/sashtml/proc/zormulas.htm ) > but it is not clear (to me at least) how teh std deviation is being > calculated in the weighted case.

Hi, Tim! Long time no see!

I read your second post, so I see you have this solved. But I wanted to toss in my $0.02 just to muddy the waters. Please bear in mind that the WEIGHT in PROC MEANS doesn't properly address the underlying problems if you have real sample data from a sample survey. If you have the classical problem of a smaple from a conceptually infinite population of independent and identically-distributed observations with normal errors, and the weights only represent a summarization for convenience, then PROC MEANS is great. If you have sample survey data from a finite population, where you can't make the traditional 'general linear model' assumptions, then you ought to be using PROC SURVEYMEANS.. which has a very different variance estimator.

David -- David Cassell, CSC Cassell.David@epa.gov Senior computing specialist mathematical statistician