FYI:
The Biostatistics Group at the Mayo Clinic (Rochester, MN) has S-Plus
functions for calculating the area under an ROC curve and making ROC plots.
Ciao,
Michael
************************************
Michael Ian Westphal, PhD Candidate
Department of Environmental Science, Policy, & Mgt
University of California at Berkeley
The Ecology Centre
Department of Zoology and Entomology
University of Queensland
St. Lucia, QLD 4072
http://www.ecology.uq.edu.au
Tel: 61 7 3365 1671
Fax: 61 7 3365 1655
Home Tel: 61 7 3719 5638
----- Original Message -----
From: "james mugodo" <jmugodo@yahoo.com>
To: <s-news@lists.biostat.wustl.edu>
Sent: Thursday, February 28, 2002 7:37 PM
Subject: [S] Wilcoxon Two-Sample Test statistic
> Hi all
>
> I have generated logistic regression models, GAMs and
> classification tree models for presence absence data.
> I want to compare their predictive performance using
> the statistic of the area under the curve of a ROC
> plot. I want to estimate the Area under the curve of a
> ROC plot by dividing the Wilcoxon two-sample test
> statistic by the product of the absence and presence
> data (Hanley and McNeil, 1982).
>
> The problem is that S-Plus gives the normal Z
> statistic without specifying the Wilcoxon two-sample
> test statistic. How can I tell S-Plus to give me the
> Wilcoxon two-sample test statistic?
>
> Any other ways of estimating the area under the curve
> of a ROC plot using S-Plus would be most appreciated.
>
> Hanley, J.A. and McNeil, B.J. (1982), "The Meaning and
> Use of the Area under a Receiver Operating
> Characteristic (ROC) Curve," Radiology, 143 29 -36.
>
> thanks and cheers
>
> James
>
>
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