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Re: st: Slow STATA


From   Neil Shephard <neil.shephard@mindless.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Slow STATA
Date   Tue, 12 Oct 2004 07:09:36 +0100

> Skimming through the Statalist archives, it looks like if you really really 
> really need Fisher's Exact Test for tables like this, then set your 
> computer running and check back every few hours\days\weeks to see if it has 
> finished yet.  Or, use software that has a faster algorithm -- in a message 
> 2 years ago Richard Goldstein suggested StatXact.  SPSS has an exact tests 
> module but I've never used it.
> 
> But, do you really need this?  Joseph Coveney has suggested one alternative 
> that may be more appropriate anyway.  Sometimes, too, people just combine 
> sparse categories and use a chi-square test.  My guess (possibly wrong) is 
> that you won't see Fisher's Exact test reported very often for tables like 
> this - 5 or 10 years ago people probably didn't have the hardware to run it 
> even if they wanted to.
> 

A program which will do all of the combining for you and derive several novel p-values for chi-squared is called clump (see net from http://www.mds.qmw.ac.uk/statgen/dcurtis/software.html ).  A version was at one stage written by Adrian Mander for Stata (although it only derives two of the four stats calculated in the standalone).  A quick search reveals that clump doesn't reside in any archives at present, and Adrian Manders web-site seems to have disapeared, but if you'd like a copy I can mail them ado and help files.

Regards

Neil
-- 
Answer   : Because it breaks the logical sequence of discussion
> Question : What's wrong with top-posting?

neil.shephard@mindless.com
neil.shephard@man.ac.uk

http://slack.ser.man.ac.uk/
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