Date: Mon, 3 Nov 2003 19:02:50 -0500
Sender: "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From: Robert Arnold <firstname.lastname@example.org>
Subject: posthoc tests in analysis of covariance
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Hi. I'm not used to working with ANCOVA, so there may be an easy way to do
what I would like to do, but haven't seen how to do. I would like to
mean scores on a family functioning measure for people in different
locations, controlling for their education and family income.
I would like to compare those in sites 1 and 2 with those in site 5 and
in site 3 with those site in 4.
The comparison is easy without the covariates. I can simply enter
ONEWAY famfunc by site with edlevel income
/ posthoc = <name of a chosen test> .
The output compares each site with each other, and I can examine the
comparisons of interest, while ignoring the rest.
According to the documentation, the posthoc subcommand is available
for UNIANOVA (the GLM univariate analysis command). When I try to
use it, though, I get a message saying that the POSTHOC command is
being ignored because there are covariates in the model. UNIANOVA
will print out the differences between each site and a chosen reference
site, but not output from POSTHOC.
Is there some other way to get comparisons between specific groups
after controlling for covariates?
Thanks in advance for your help.