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Date:         Tue, 6 May 2008 10:30:24 -0700
Reply-To:     Amy Smith <asmith197401@YAHOO.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Amy Smith <asmith197401@YAHOO.COM>
Subject:      Re: Is it true that a zero-inflated Gamma model is not possible
              in either GENMOD or NLMIXED?
Comments: To: Wensui Liu <liuwensui@GMAIL.COM>
Content-Type: text/plain; charset=iso-8859-1

I'm trying to do a two-part model that is partly like a logistic regression on whether or not a person has costs and partly like a glm with link=log and dist=gamma if that person has costs.  See my email below. ----- Original Message ---- From: Wensui Liu <liuwensui@GMAIL.COM> To: SAS-L@LISTSERV.UGA.EDU Sent: Tuesday, May 6, 2008 1:17:43 PM Subject: Re: Is it true that a zero-inflated Gamma model is not possible in either GENMOD or NLMIXED? do you know the probablity function of the model you wanted? On 5/5/08, Amy Smith <asmith197401@yahoo.com> wrote: > Has anyone found a procedure in SAS for creating a zero-inflated Gamma model?  My response variable is cost.  I have a class variable called group that has three levels Intervention1, Intervention2, and Control. >  The following two models succeed without any problem. >  PROC GENMOD; >    CLASS group; >    MODEL cost = group / LINK=log DIST = bin; >  PROC GENMOD; >    CLASS group; >    MODEL cost = group / LINK=log DIST = gamma; >  I cannot figure out how to get GENMOD to join these to give a zero-inflated gamma model.  Or I thought maybe NLMixed could handle this model but I cannot get the syntax to work right and I'm now questioning if it is even possible.  Has anyone ever written SAS code that successfully runs on a zero-inflated gamma?  I would really love to see the syntax on a simple example like I have here. >  Thanks for your help! > > > >      ____________________________________________________________________________________ >  Be a better friend, newshound, and >  know-it-all with Yahoo! Mobile.  Try it now.  http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ > -- =============================== WenSui Liu ChoicePoint Precision Marketing Phone: 678-893-9457 Email : wensui.liu@choicepoint.com Blog  : statcompute.spaces.live.com =============================== ____________________________________________________________________________________ Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now.. http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ


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