Date: Wed, 29 Oct 2003 08:49:06 +0000
Reply-To: Muir Houston <email@example.com>
Sender: "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From: Muir Houston <firstname.lastname@example.org>
Subject: Re: qu. about choosing reference groups
Content-Type: text/plain; charset="us-ascii"
If you want to choose category 2 then you need to construct 3 'dummy'
variables and then put the dummy variables for catefgories 1 & 3 into
model 2 is then reference
this can be done with all catgorical variables to allow specific
selection of reference group
as to the last point - in the specification did it say it had included
all variables in the model?
what enter method are you using? bacward stepwise, forward stepwise,
>>> jwegbrei <jwegbrei@HSPH.HARVARD.EDU> 10/27/03 10:42pm >>>
i'm doing logistic regression and have categorical predictor variables.
having difficulty choosing reference groups for those predictor
when defining my variables as categorical i have chosen a simple
i chose the 'first' reference category, will it use the category coded
(if 1,2,3, categories) as the reference group? and if i chose 'last'
then use '3' as the reference category. and what should i do if i want
'2' as my reference category? is there any way of specifying a
category besides the first or last?
last, what should i do if after choosing chosing a simple contrast and
the first reference category and then running my regression, the
categories don't appear in the output and only the variable name
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