Date:         Wed, 30 Sep 2009 19:22:07 -0400
Reply-To:     Peter Flom <peterflomconsulting@mindspring.com>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Peter Flom <peterflomconsulting@MINDSPRING.COM>
Subject:      Re: Poisson
Content-Type: text/plain; charset=UTF-8

>On Wed, Sep 30, 2009 at 3:33 PM, Shawn Haskell (I think) wrote

>> very good - thanks for that WenSui.  What's the latest on under-
>> dispersion if you can help there too?  I have counts (response
>> variable) of 0-4.  It is not a ZIP situation, and deviance/df < 0.5.
>> The scale parameter being <1 artificially reduces Type-3 SEs and p-
>> values.  So, I switched to an ordinal logistic model that seems to fit
>> the data much better according to AICc.  Any other thoughts?  thanks.
>> Shawn

Could I ask what your DV is?  I haven't run into an underdispersion case.

Peter

Peter L. Flom, PhD
Statistical Consultant
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