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RE: st: Help about Ranksum - porder option


From   Óscar Becerra-CERAC <orbecerra@gmail.com>
To   <statalist@hsphsun2.harvard.edu>
Subject   RE: st: Help about Ranksum - porder option
Date   Mon, 31 Oct 2005 12:36:14 -0500

Thanks, and can anyone suggests to me a procedure to perform this test?

Óscar

-----Mensaje original-----
De: owner-statalist@hsphsun2.harvard.edu
[mailto:owner-statalist@hsphsun2.harvard.edu] En nombre de Richard Goldstein
Enviado el: Lunes, 31 de Octubre de 2005 11:40 a.m.
Para: statalist@hsphsun2.harvard.edu
Asunto: Re: st: Help about Ranksum - porder option

porder is taking all possible pairs (control=yes paired with each control=
no) and asking in what percent of those pairs is No larger than YES; this
does not appear to be the question you are asking; if I correctly understand
your question, I think you want a parametric procedure rather than the
rank-sum test

hope this helps
Rich

Óscar Becerra-CERAC wrote:

> Hi all,
> 
> I am applying a Wilcoxon test for the equality of distributions, 
> between two control groups with the ranksum command. But I have a 
> doubt about the interpretation of the result of this test. The obtained
result is:
> 
> ranksum series , by(control) porder
> 
> Two-sample Wilcoxon rank-sum (Mann-Whitney) test
> 
>   control    |      obs    rank sum    expected
> -------------+---------------------------------
>           NO |     2284     3280197     3338066
>          YES |      638      990306      932437
> -------------+---------------------------------
>     combined |     2922     4270503     4270503
> 
> unadjusted variance   3.549e+08
> adjustment for ties  -5118462.8
>                      ----------
> adjusted variance     3.498e+08
> 
> Ho: series(control==NO) = series(control==YES)
>              z =  -3.094
>     Prob > |z| =   0.0020
> 
> P{series(control==NO) > series(control==YES)} = 0.460
> 
> 
> According with the p - value, I understand that the distribution 
> between – groups changes, but I can’t understand the result obtained 
> by the p order option. What I really want to know is if when my 
> control measure is on it has a positive impact in the behaviour of series.
Can you help me with this?
> 
> Thanks,
> 
> 
> 
> Óscar Becerra
> Researcher
>  
> Conflict Analysis Resource Center
> Carrera 10 N° 65 - 35 Of. 603
> Tels: +(571) 345 85 72/3
> www.cerac.org.co
> 
> 

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