Re: st: RE: RE: Svytab subgroup analysis with more than two subgroups

["L Allen" <indiananonprofit@hotmail.com>]

That is what I want.  However, the problem I ran into when constructing the 
subgroup, both previously and as suggested below, is that the 3 groups not 
in the subgroup are still levels in the groupvar and generate a 0 count in 
half the cells in the table.  With zeros in the marginals, a chi-square 
cannot be computed.

Richard Clerkin
Ph.D. Student
Indiana Nonprofit Project
Indiana University-Bloomington



> From: Lee Sieswerda <Lee.Sieswerda@tbdhu.com>
> Reply-To: statalist@hsphsun2.harvard.edu
> To: "'statalist@hsphsun2.harvard.edu'" <statalist@hsphsun2.harvard.edu>
> Subject: st: RE: RE: Svytab subgroup analysis with more than two subgroups
> Date: Mon, 21 Jul 2003 09:31:24 -0400
>
> I'm not sure that I completely understand your problem either, but 
> something
> like this:
>
> tab groupvar, gen(group)
> gen dichot = (group1==1 | group2==1 | group3==1)
> svytab groupvar catvar, subpop(dichot)
>
> would give you a chi-square test for the association between groupvar and
> catvar for three out of your six groups. Is that not what you are looking
> for?
>
> Lee Sieswerda, Epidemiologist
> Thunder Bay District Health Unit
> Lee.Sieswerda@tbdhu.com
>
>
> -----Original Message-----
> From: L Allen [mailto:indiananonprofit@hotmail.com]
> Sent: Monday, July 14, 2003 1:56 PM
> To: statalist@hsphsun2.harvard.edu
> Subject: st: Svytab subgroup analysis with more than two subgroups
>
>
> Dear Statalist,
>
> We have survey data with 39 strata.  We have categorized the respondents
> into 6 groups. This grouping was not used in the sampling design (it is not
> one of our stratifying variables).  We want to do a svytab on 3 of the 6
> groups against responses to a categorical variable; however, the survey
> manual warns us not to us an if restriction to select these three groups
> because it will not produce correct statistics and variance estimates.
> However, the subpop() option does  not appear to meet our needs either
> because we want to test the association among these three groups.  Any
> suggestions on how to proceed would be appreciated.
>
> Richard Clerkin
> Ph.D. Student
> Indiana Nonprofit Project
> Indiana University-Bloomington
>
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