Date:         Wed, 6 Sep 2006 22:44:40 -0700
Reply-To:     David L Cassell <davidlcassell@MSN.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         David L Cassell <davidlcassell@MSN.COM>
Subject:      Re: proc loes and binary depedent variable
In-Reply-To:  <200609041440.k84AkXBw007585@mailgw.cc.uga.edu>
Content-Type: text/plain; format=flowed

adel_tangi@YAHOO.FR wrote:
>
>Dear All,
>   Is there any one in the list, who has an example for using proc loess
>with binary dependent variable and one or multiple independent variables?
>
>   Many thanks
>
>   Adel
>

I would not recommend LOESS for a binary dependent variable.

LOESS can certainly handle multivariate data.  But the fit is done
as a weighted least squares model of linear and/or quadratic forms
of the regressors.  So using it as is, on categorical data, is not the
best idea.

Instead, I would look into PROC GAM.  It can fit splines and
other nonparametric models, as well as semi-parametric models
and parametric models, and it can fit them to binary dependent
variables too.

But if you fit a complex nonparametric model to your data,
will you be able to answer the hypotheses you had originally?

HTH,
David
--
David L. Cassell
mathematical statistician
Design Pathways
3115 NW Norwood Pl.
Corvallis OR 97330

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