Date:         Wed, 15 Oct 2008 10:55:54 -0700
Reply-To:     cgoldhaw <cgoldhaw@HOTMAIL.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         cgoldhaw <cgoldhaw@HOTMAIL.COM>
Organization: http://groups.google.com
Subject:      Re: Proper use of proc logistic
Comments: To: sas-l@uga.edu
Content-Type: text/plain; charset=ISO-8859-1

Once again, huge thanks to everyone for replying. I'm new to SAS and
statistics does not come easy to me.

The variables that I am dealing with would logically be highly
correlated.  They are feed intake, average time spent feeding and
average number of visits to a feeder (all of which are related, so now
that I have read your helpful comments, I see that it makes little
sense to have them all in the same model).

To make practical recommendations about which variable is "the best"
at predicting disease/has the most impact on disease outcome, i
thought that it made the most sense to run each DV independently. But
as Sigurd Hermansen mentioned, the significance of a model with one DV
is suspect.  When I plot the residuals for each DV there are no
patterns and each DV shows a normal distribution. There are ten
animals in the healthy group and ten in the diseased group, balanced
for age and other factors known to influence disease and/or feed
intake.

Would it be correct to run each DV independently and based on the
significance level or r^2 make recommendations as to which DV is best
suited for identifying animals at increased risk of disease??