| Date: | Mon, 12 Nov 2007 15:33:30 -0800 |
| Reply-To: | Maurice Melancon <dmso12@GMAIL.COM> |
| Sender: | "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU> |
| From: | Maurice Melancon <dmso12@GMAIL.COM> |
| Subject: | Help with nested terms in PROC MIXED |
| In-Reply-To: | <87ba8bf70711121529i71921093o48712d75beeaf767@mail.gmail.com> |
| Content-Type: | text/plain; charset=ISO-8859-1 |
Hello, I'm new to mixed models, having run essentially all of my data
for my dissertation using GLM. Normally, we'd have chosen 12 mice
families (strains = 6 are cancer-prone, 6 are not) and would measure
gene expression as a function of time, family, strain, and the
interaction of time and strain using:
CLASS TIME STRAIN FAMILY;
MODEL p53 = TIME STRAIN FAMILY(STRAIN) TIME* STRAIN;
LSMEANS TIME*STRAIN
#contrast statements, etc. using the nested term to 'block' for
families. There is a different gene that was unanticipated, and we
have re-classified families into different STRAINS which requires a
random model. My limited understanding of code would be:
CLASS TIME STRAIN FAMILY;
MODEL p53 = TIME STRAIN TIME* STRAIN;
RANDOM FAMILY(STRAIN);
Does this model accomplish testing the nested term over the error and
properly treat the random variable? Suggestions or reading would be
appreciated.
Thanks,
Maurice
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