st: Re: Repeated measures with covariates

["Joseph Coveney" <jcoveney@bigplanet.com>]

May Lebanan wrote:

Hi, I am doing an analysis on a dependent variable called RExp
measured on several follow-up times (Ffupno) and would like to compare
among 4 groups (grp) and sex and would like to include a covariate
Hemoglobin.  Without the covariate my anova model looks like this:

anova RExp grp sex sex#grp / Respcode|grp#sex Ffupno Ffupno#grp
Ffupno#sex Ffupno#grp#sex, repeated(Ffupno)

Now I cannot find a reference on how to incorporate a covariate in this model.
What if I want to add several covariates, would that be possible and
what would the command look like?  Please help.

--------------------------------------------------------------------------------

How to incorporate your hemoglobin covariate into the repeated-measures ANCOVA
model depends upon whether hemoglobin concentration is measured at each
follow-up observation (a so-called time-varying covariate) or is measured only
once, for example, at baseline (a time-invariant covariate).  See this thread
for specifics about how to do each:
http://www.stata.com/statalist/archive/2004-01/msg00032.html .

Joseph Coveney


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