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RE: st: Kwallis in a loop [now p-value of the Kwallis]


From   "Nick Cox" <n.j.cox@durham.ac.uk>
To   <statalist@hsphsun2.harvard.edu>
Subject   RE: st: Kwallis in a loop [now p-value of the Kwallis]
Date   Sun, 13 Nov 2005 17:24:03 -0000

Your answer strengthens my previous argument.

-makematrix- just cannot fulfil all the expectations
you have of it. If you omit the spaces in 

max(chiprob(r(df), r(chi2_adj) + 1e-20),.0001) 

to 

max(chiprob(r(df),r(chi2_adj)+1e-20),.0001) 

you might get -makematrix- to behave the way you want, 
as the argument of -from()- is parsed on spaces, 
but you are still ignoring my strong advice not to do it
this way. 

I am at a loss to see why you prefer this route to 
that of a program designed to tackle your problem 
directly. No programming on your part is required. 

Nick 
n.j.cox@durham.ac.uk 

Herve STOLOWY
 
> Dear Nick:
> 
> Sorry for this late reply. I tried your program and it works 
> perfectly. I thank you very much.
> 
> Although I perfectly read what you wrote about -makematrix-, 
> I still like this command and my level of programming is not 
> good enough to write the program you designed for me.
> 
> So, I would have an additional question, hopefully more simple.
> 
> With a ranksum test, I learnt from prior postings how to get a matrix:
> 
> makematrix m1, from(r(z) 2*normprob(-abs(r(z)))) label : 
> ranksum prov_ass, by( sodas2cl)
> 
> I woud like to do the same with -kwallis-. In your program, I 
> found the following formula which seems to be the computation 
> of the p-value of the kwallis: 
> 
> max(chiprob(r(df), r(chi2_adj) + 1e-20),.0001) 
> 
> Then, I wrote the following command with -makematrix-: 
> 
> makematrix m2, from(r(chi2_adj)   max(chiprob(r(df), 
> r(chi2_adj) + 1e-20),.0001) ) label : kwallis prov_ass, by(sodas3cl)
> 
> Unfortunately, it does not work. I get the following error message:
> 
> invalid '.0001' 
> r(198);
> 
> I obviously did something wrong.
> 

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