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RE: st: ttest var1==var2 for clustered data


From   Nick Winter <nw53@cornell.edu>
To   statalist@hsphsun2.harvard.edu
Subject   RE: st: ttest var1==var2 for clustered data
Date   Tue, 22 Mar 2005 09:47:22 -0500

How about

  . generate diff = var1-var2
  . svymean diff
  . text diff=0

?

--Nick Winter

At 02:28 PM 3/22/2005 +0000, you wrote:
> The problem is, we want to perform a mean comparison between
> two variables
> (paired t-test) and not between two subgroups. The syntax
> without adjusting
> for the clustering is  "ttest var1=var2", thus using inflated
> degrees of
> freedom, 'cause no adjustment for the clustering of the data
> is possible.
> In contrast performing the test with a disaggregated file
> would result in
> deflated degrees of freedom...
> For our group comparisons we exactly use your proposition.

Rich Goldstein

> >a t-test is a simple regression where the only predictor is the dummy
> >variable identifying the groups -- so, put the two variables
> into one long
> >variable; add a group identifier and use regression with the
> cluster option

Christian Hunkler
--------------------------------------------------------
Nicholas Winter 607.255.8819 t
Assistant Professor 607.255.4530 f
Department of Government nw53@cornell.edu e
308 White Hall falcon.arts.cornell.edu/nw53 w
Cornell University
Ithaca, NY 14853-4601

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