Date:         Wed, 20 Dec 2006 13:16:47 -0500
Reply-To:     Jake Bee <johbee@GMAIL.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Jake Bee <johbee@GMAIL.COM>
Subject:      Re: proc mixed for 2 groups (Placebo and all Active Treatment
              Combined)
Comments: To: Robin High <robinh@unlserve.unl.edu>
In-Reply-To:  <Pine.A41.4.02.10612201104470.39600-100000@unlunix.unl.edu>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Because I have to do this by weeks and there is a comparison from week==0
which is baseline and the comparison over all the weeks from baseline is
change from baseline.

Thanks!

Jake


On 12/20/06, Robin High <robinh@unlserve.unl.edu> wrote:
>
>
>
> > Previous I asked this group for a proc mixed solution for Placebo vs.
> > Multiple Treatment Groups and a Dunnett Test,
> > and the answer was correct.  I'm not a statistician (programmer).  The
> > solution was:
> >
> > proc mixed data=rx_1;
> >  by week;
> >   class center_eff treatment;
> >    model rx_change_rx = rx_baseline center_eff treatment / solution;
> >    lsmeans treatment / diff=control cl adjust=dunnett;
> >   run;
> > quit;
> >
>
> > Can this be setup for a T-Test for the 2 Treatment Groups Placebo vs.
> > Active Groups (i.e. combined)
>
> Jake,
>
> proc mixed data=rx_1;
> by week;
> class center_eff treatment;
> model rx_change_rx = rx_baseline center_eff treatment / solution cl;
> lsmeans treatment / diff cl;
> run;
>
> If treatment has two groups (active and placebo) and you want to compare
> two means like a t-test, then the LSMEANS statement as above will do it.
>
> Also, the "solution" pvalue for treatment and the type 3 table from the
> MODEL statement will also give you the same results. And while we're at
> it:
>
> ESTIMATE 'active vs placebo' treatment 1 -1 / cl;
>
> will also compute it.
>
> Other items of interest is the name of the term center_eff -- is that
> factor actually considered fixed, or could it be entered as a random
> effect on a RANDOM statement?
>
> RANDOM center_eff ;
>
> (and thus removed from the MODEL statement).
>
> And why is
>
> BY week;
>
> entered?  My next question, is there repeated measures on the same
> subjects over time (unless, of course, you have different subjects each
> week, then ignore this Q.).
>
> Robin High
>
>
>