Re: st: exact logistic regression

["Michael N. Mitchell" <Michael.Norman.Mitchell@gmail.com>]

Dear Nick

  I created an example based on the -auto- dataset like this...

clear all
sysuse auto
replace rep78 = rep78 - 1 if rep78 !=1
tab rep78
expand 28
keep in 1/2061
xi: exlogistic foreign i.rep78 , memory(1400m)

  and I was not able to complete this either, getting the message

observation 415: enumerations =    9333408
observation 416: enumerations =    9470664
the operating system refuses to provide the requested memory
r(909);

  Do you have a very small or empty cell when you crosstabulate -a- by -b-? Perhaps you 
could share the crosstab of -a- and -b- with us to illustrate the need for exact logistic 
regression?
Best regards,

Michael N. Mitchell
Data Management Using Stata      - http://www.stata.com/bookstore/dmus.html
A Visual Guide to Stata Graphics - http://www.stata.com/bookstore/vgsg.html
Stata tidbit of the week         - http://www.MichaelNormanMitchell.com



On 2010-06-21 12.29 PM, Nikolaos Pandis wrote:
> Hi to all.
>
> 1. I try to run in Stata 11 IC:
>
> xi:exlogistic a i.b
> a= binary (0,1)
> b=4 level categorical (0-3)
> 2061 observations
>
> I get the following error message:
> exceeded memory limit of 10.0M bytes; use the memory() option to increase the memory limit
> error(499)
>
> I use set memory to values larger than 10m and still get the same message.
>
> exceeded memory limit of 10.0M bytes; use the memory() option to increase the memory limit
> error(499)
>
> 2. I was wondering if it is possible to run multinomial logistic regression using exact methods.
>
>
> Any comments would be appreciated.
>
> Many thanks,
> Nick
>
>
>
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