On Thu, 31 Jul 2003 17:45:01 +0200
AHC van Kampen <a.h.vankampen@amc.uva.nl> wrote:
> Hi,
>
> I'm new to logistic regression and therefore this stupid question:
>
> What I have understand from logistic regression is that the binary
> response variable is transformed to log(p/(1-p)).
> 1) How is the fraction p calculated for an individual response value (0
> or 1). Probably, if for a certain predictor value only 1 response is
> available the fraction is aslo always 1 or 0, or is the fraction p
> calculated a pre-specified range for a predictor value?
It would be best to read a book or tutorial article on logistic regression
first. Your question misses the point.
>
> 2) I'm analysing the Kyphosis dataset that comes with Splus. How are
> these binary response values transformed and how can i check in Splus
> how this was done. Is there any variable that contains the transformed
> response values?
See above. You don't transform the binary responses.
Frank
>
> Any help is appreciated
>
> --
> ---------------------------------------
> | Dr. Antoine H.C. van Kampen |
> | Academic Medical Center Amsterdam |
> | Bioinformatics Laboratory |
> | K2-211 |
> | Postbus 22660 |
> | 1100 DD Amsterdam, the Netherlands |
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> | Phone: ++31-20-5667096 |
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> | Email: a.h.vankampen@amc.uva.nl |
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Frank E Harrell Jr Prof. of Biostatistics & Statistics
Div. of Biostatistics & Epidem. Dept. of Health Evaluation Sciences
U. Virginia School of Medicine http://hesweb1.med.virginia.edu/biostat
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