Date: Fri, 7 Jan 2011 18:44:57 -0600
Reply-To: Robin R High <rhigh@UNMC.EDU>
Sender: "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From: Robin R High <rhigh@UNMC.EDU>
Subject: Re: Logistic Regression Intercept Pr>Chisq
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The pvalue for the intercept that is not-significant implies that it is
close to 0 (on the logit scale?). If you set all the other explanatory
data to 0, the intercept becomes a reference value so to speak, to predict
the probability of a success, which implies a 50/50 occurrence of the
prob(y=1) = EXP(0) / (1 + EXP(0))
I would keep it in the model (and I assume by backward selection you
selected variables essentially on your own and not the code generated
Tanmoy Mukherjee <tkmcornell@YAHOO.COM>
01/07/2011 06:17 PM
Logistic Regression Intercept Pr>Chisq
"SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
I am running a Binomial Logistic Regression and I am getting some weird
result with regards to the Intercept values. I will appreciate if someone
can shed some light on the interpretaion of the same.
Data set :
Total Number of observations 351877
Response =1 9511
Modeling probability of response=1
Using Backward selection method to compute the best model
Wald Chi Square 0.38
Based on this does this mean that we should reject the Intercept.
I will appreciate if someone can please explain this.
Thanks and Regards,
Tanmoy Kumar Mukherjee
3 Perrine Court,
East Brunswick, NJ 08816