|Date: ||Mon, 19 Feb 1996 17:04:04 EST|
|Sender: ||"SAS(r) Discussion" <SAS-L@UGA.CC.UGA.EDU>|
|From: ||Shylendra Kumar <KUMARS@WOODS.UML.EDU>|
|Subject: ||PROC NESTED question|
A query for users of PROC NESTED:
We would like to know if anyone else has used nested ANOVA where the
hierarchy of nesting was somewhat ambiguous, or simply has experimented
with alternate sequences of variables in the CLASS statement.
We have an unbalanced data set, in which the structure of data collection
does not dictate a clear hierarchy such as that in the example given in
the SAS Manual. We also have a strong 'a priori' belief about how the
nesting should be structured, based on which variables ought to determine
other variables. But as we were trying to understand better how the
procedure works, degrees of freedom, etc., we tried reversing two of the
terms in the nesting hierarchy. It had such a dramatic effect on our
results that we were left a bit uncertain as to how to report them.
Clearly our findings are correct only if our 'a priori' hypothesis is
also correct - but there is no obvious way to test the latter.
Has anyone else looked at this?
Also, who can suggest a more up-to-date biostat text on nested ANOVA
than the refs in the SAS Manual?
Thanks a lot in advance.