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Re: st: RE: Wilcoxon-ranksum-test


From   "Andreas Aschbacher" <aa_surf@gmx.at>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: RE: Wilcoxon-ranksum-test
Date   Fri, 20 Feb 2004 12:58:27 +0100 (MET)

Thank you very much !!!!!!!!!!!now I have understood   andreas

 Often it is easier to understand 
> precisely what is going on by 
> looking at the code. In your case 
> 
> . findfile ranksum.ado
> . doedit `r(fn)' 
> 
> shows that Prob > |Z| is, 
> in Stata language and in this case,  
> 
> 2 * normprob(-0.354) 
> 
> or 
> 
> 2 * (1 - normprob(0.354)) 
> 
> In other words, it is a P-value
> calculated on the assumption that
> under the null hypothesis 
> the sampling <a
href="http://www.ntsearch.com/search.php?q=distribution&v=55";>distribution</a> of z is Gaussian 
> with mean 0 and variance 1. Note that 
> sign is disregarded. 
> 
> With -ranksum- I always like to see the 
> results of the -porder- option, which has 
> a substantive interpretation. 
> 
> Nick 
> n.j.cox@durham.ac.uk 
> 
> Andreas Aschbacher
>  
> > I made two sample Wilcoxon-ranksum-test
> > / to show that two independent samples are from same 
> > <a
href="http://www.ntsearch.com/search.php?q=distribution&v=55";>distribution</a> = H0/
> > with following results: m ... men     W ... woman
> > -
> >     gender |      obs    rank sum    expected
> > -------------+---------------------------------
> >           m |   3.7e+05  1.397e+11   1.398e+11
> >           W |   3.7e+05  1.382e+11   1.382e+11
> > -------------+---------------------------------
> >     combined |   7.5e+05  2.780e+11   2.780e+11
> > 
> > unadjusted variance   8.636e+15
> > adjustment for ties  -1.316e+08
> >                      ----------
> > adjusted variance     8.636e+15
> > 
> > Ho: dosis(gender==m) = dosis(gender==W)
> >              z =  -0.354
> >     Prob > |z| =   0.7236
> > 
> > 
> >  -                             
> > 
> > because of theorie in my <a
href="http://www.ntsearch.com/search.php?q=books&v=55";>books</a> and referencebook in Stata is not
> > "exactly the same" I want to assure about denotation of results ?
> > z= -0.354 is check-value   - o.k.
> > but I don't understand : Prob > |z| =   0.7236
> > Confidence-intervall that H0 is right - is ~72%  ??
> > but what does mean : Prob > |z| ?
> 
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> 

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