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RE: st: adjusted Mann-Whitney/Wilcoxon test


From   Ricardo Ovaldia <ovaldia@yahoo.com>
To   statalist@hsphsun2.harvard.edu
Subject   RE: st: adjusted Mann-Whitney/Wilcoxon test
Date   Thu, 9 Apr 2009 17:08:10 -0700 (PDT)

Thank you Roger. I would like to use -somersd-, but I keep getting an error. What am I doing wrong?

Here using the cancer data.

. which somersd
c:\ado\stbplus\s\somersd.ado
*! Author: Roger Newson
*! Date: 04 August 2008

. sysuse cancer
(Patient Survival in Drug Trial)

. somersd   died age , cluster(  drug )
       tidotforsomersd():  3499  tidottree() not found
                 <istmt>:     -  function returned error
r(3499);


Thank you,
Ricardo

Ricardo Ovaldia, MS
Statistician 
Oklahoma City, OK


--- On Thu, 4/9/09, Newson, Roger B <r.newson@imperial.ac.uk> wrote:

> From: Newson, Roger B <r.newson@imperial.ac.uk>
> Subject: RE: st: adjusted Mann-Whitney/Wilcoxon test
> To: "'statalist@hsphsun2.harvard.edu'" <statalist@hsphsun2.harvard.edu>
> Date: Thursday, April 9, 2009, 3:39 PM
> As David said, the -somersd- package, downloadable from SSC,
> can estimate stratified versions of rank parameters. The
> user has a choice of parameters, which may be Kendall's
> tau-a, Somers' D, or a Theil-Sen median slope. All of
> these parameters are available in stratified versions,
> restricted to comparisons within strata defined by a
> categorical variable. And the -somersd- package has 3 .pdf
> manuals, which the user can download with the package, in
> which the methods and formulas are explained.
> 
> I hope this helps.
> 
> Best wishes
> 
> Roger
> 
> 
> Roger B Newson BSc MSc DPhil
> Lecturer in Medical Statistics
> Respiratory Epidemiology and Public Health Group
> National Heart and Lung Institute
> Imperial College London
> Royal Brompton Campus
> Room 33, Emmanuel Kaye Building
> 1B Manresa Road
> London SW3 6LR
> UNITED KINGDOM
> Tel: +44 (0)20 7352 8121 ext 3381
> Fax: +44 (0)20 7351 8322
> Email: r.newson@imperial.ac.uk 
> Web page: http://www.imperial.ac.uk/nhli/r.newson/
> Departmental Web page:
> http://www1.imperial.ac.uk/medicine/about/divisions/nhli/respiration/popgenetics/reph/
> 
> Opinions expressed are those of the author, not of the
> institution.
> 
> -----Original Message-----
> From: owner-statalist@hsphsun2.harvard.edu
> [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of
> David Airey
> Sent: 09 April 2009 18:23
> To: statalist@hsphsun2.harvard.edu
> Subject: Re: st: adjusted Mann-Whitney/Wilcoxon test
> 
> To me, stratified generally means controlling for a
> non-continuous  
> covariate.
> 
> -Somersd- provides rank-based statistics for group
> comparisons  
> allowing for strata.
> 
> -Dave
> 
> On Apr 9, 2009, at 10:45 AM, Constantine Daskalakis wrote:
> 
> > I have the same question as Ricardo.
> >
> > By stratified, we mean controlling for another
> covariate:
> >
> > Wilcoxon of Y by X, controlling for Z
> >
> > StatXact does this stratified Wilcoxon.
> >
> >
> > David, the parallel is Mantel-Haenszel for dichotomous
> outcome.
> >
> > So, the command would look something like this:
> >
> > ranksum y x, by(z)
> >
> > or
> >
> > ranksum y, by(x) strata(z)
> >
> >
> > On 4/9/2009 10:44 AM, David Airey wrote:
> >> .
> >> If ttest generalizes to regress, then ranksum
> generalizes to what?
> >> There is a lot of literature on ranksum tests with
> clustered data  
> >> if that's what you mean. Maybe you can define
> your data more  
> >> precisely...
> >> On Apr 9, 2009, at 8:44 AM, Ricardo Ovaldia wrote:
> >>>
> >>> Dear all,
> >>>
> >>> Is there a way to adjust the -ranksum- test
> for covariates? Or is  
> >>> there another way to do an adjusted
> Mann-Whitney U test? Something  
> >>> similar to relationsip between ttest and
> regress.
> >>>
> >>> Thank you,
> >>> Ricardo.
> >>>
> >>> Ricardo Ovaldia, MS
> >>> Statistician
> >>> Oklahoma City, OK
> >
> >
> >
> > -- 
> >
> >
> > The documents accompanying this transmission may
> contain confidential
> > health or business information. This information is
> intended for the
> > use of the individual or entity named above. If you
> have received
> > this information in error, please notify the sender
> immediately and
> > arrange for the return or destruction of these
> documents.
> >
> > Constantine Daskalakis, ScD
> > Associate Professor,
> > Thomas Jefferson University, Division of Biostatistics
> >   1015 Chestnut St., Suite M100, Philadelphia, PA
> 19107
> >   Tel: 215-955-5695
> >   Fax: 215-503-3804
> >   Email: c_daskalakis@mail.jci.tju.edu
> >   Webpage:
> http://www.jefferson.edu/clinpharm/biostatistics/
> >
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