Date:         Tue, 3 Dec 2002 17:35:21 +0100
Reply-To:     MDN <dnivet@JOUY.INRA.FR>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         MDN <dnivet@JOUY.INRA.FR>
Organization: I.N.R.A
Subject:      Proc lifetest and strata statement
Content-Type: text/plain; charset=us-ascii

Dear sas'ers,

   We want to analyze survival times in two groups of animals A, B. Data
for
each group were collected from several replicates (20 for each group).
These replicates are nested within the groups. In each replicate, there
were 60 animals. So that, we have a model with groups (2 levels) and
replicates within groups.

We want to use the LIFETEST procedure with log-rank test to check the
effect of
the group.
How can we specify the nested design in Lifetest procedure ? Is the
STRATA statement suitable for this ?

If nested designs are not possible with Lifetest, is there any
equivalent procedure which would accept nested designs ?

Thank you for help.
Mathilde Dupont-Nivet
INRA
Fish genetics lab.
France
dnivet@jouy.inra.fr