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Re: st: Re: Repeated measures with covariates


From   May Lebanan <mlebanan@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Re: Repeated measures with covariates
Date   Mon, 27 Aug 2012 14:49:11 +0800

Thank you Dr. Coveney.  I will try the time-invariant covariate in the model.

Another question, after running the anova command, we can use the
anovaplot or margins then marginsplot.  However, I am not getting the
same values/graph similar to the means using the command 'table' (If i
have 2 independent categorical variables only, no covariate).  Is
there a command that can do this, aside from resorting to the use of
table command then doing the graphs in excel?

On Sun, Aug 26, 2012 at 10:28 PM, Joseph Coveney <jcoveney@bigplanet.com> wrote:
> 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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-- 
May Antonnette O. Lebanan
Researcher Biostatistician
Indicium Research Services --> click to see the Facebook page
mlebanan@gmail.com
*
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