LISTSERV at the University of Georgia
Menubar Imagemap
Home Browse Manage Request Manuals Register
Previous (more recent) messageNext (less recent) messagePrevious (more recent) in topicNext (less recent) in topicPrevious (more recent) by same authorNext (less recent) by same authorPrevious page (November 2004, week 4)Back to main SAS-L pageJoin or leave SAS-L (or change settings)ReplyPost a new messageSearchProportional fontNon-proportional font
Date:   Wed, 24 Nov 2004 10:06:47 -0800
Reply-To:   cassell.david@EPAMAIL.EPA.GOV
Sender:   "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:   "David L. Cassell" <cassell.david@EPAMAIL.EPA.GOV>
Subject:   Re: Calculation of weighted std error of mean
Comments:   To: Tim Churches <tchur@OPTUSHOME.COM.AU>
In-Reply-To:   <41A37444.5000401@optushome.com.au>
Content-type:   text/plain; charset=US-ASCII

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


Back to: Top of message | Previous page | Main SAS-L page