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st: RE: weird ROC curve


From   "Cleves, Mario A" <ClevesMarioA@uams.edu>
To   "'statalist@hsphsun2.harvard.edu'" <statalist@hsphsun2.harvard.edu>
Subject   st: RE: weird ROC curve
Date   Fri, 6 Dec 2002 07:52:29 -0600

Arnold Kester <mailto:arnold.kester@stat.unimaas.nl> asked: 

>I just produced the weirdest ROC curve I've ever seen, and I suspect there's a bug in roctab. >The curve jumps up and down which is by definition not possible. For your amusement and 
>curiosity I append the data. I am aware that as a diagnostic, x is worthless to predict y.

I suspect that Arnold has one of several pathologic data cases that are better analyzed using Lorenz-like curves as proposed by Lee(1999), and referred to on page 138 of the Q-St Reference manual.

Regards,
Mario.  

-------------------------------------------------------------------------------------------------------------
Mario A. Cleves, Ph.D.
Associate Professor and Senior Biostatistician
UAMS, Department of Pediatrics
Arkansas Center for Birth Defects Research and Prevention
11219 Financial Centre Parkway, Suite 250
Little Rock, AR  72211
Telephone: 501-364-5001
Fax: 501-364-5107
Email: ClevesMarioA@uams.edu
-------------------------------------------------------------------------------------------------------------
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