Date: Tue, 29 Oct 2002 16:42:12 -0800
Reply-To: Jonathan Greenberg <greenberg@UCDAVIS.EDU>
Sender: "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From: Jonathan Greenberg <greenberg@UCDAVIS.EDU>
Subject: Longitudinal data analysis question?
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Hi there, I'm trying to analyze longitudinal data, with a known model:
I have 61 observations, 4 variables per observations, and they were recorded
on 5 unevenly spaced dates. The model should be exponential, so for each
Variable[t] = Variable * e ^ (k * t)
I want to be able to estimate Variable and k for each observation, or, if
possible, derive a single model assuming the rates, k, for all observations
are constant, but the starting times, Variable, might be different.
I think PROC MIXED might be able to do this, but am a SAS newbie. Any
suggestions? I want to know, for any variable value, what is the time
elapsed since the initial time?