[R] why does glm.predict give values over 1 ?

[Austin, Matt]

If you left the type argument to the predict method then your predictions
are on the log-odds scale.  Try using the type='response' in the predict
method for glm.

--Matt

> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch
> [mailto:r-help-bounces at stat.math.ethz.ch]On Behalf Of Rohit Singh
> Sent: Monday, October 31, 2005 2:52 PM
> To: r-help at stat.math.ethz.ch
> Subject: [R] why does glm.predict give values over 1 ?
> 
> 
> Hi,
> 
>  This is a newbie question. I have been using glm to perform 
> some logistic
> regression. However, if I take the fitted parameters (as part 
> of the glm
> object) and pass them on the glm.predict function, for some 
> test cases I
> am getting predicted values that are a little over 1.  This is a bit
> puzzling for me, because my understanding was that these numbers are
> probabilities and so should be between 0 and 1.
> 
> 
> Thanks a lot! I'd appreciate any help you could provide.
> 
> -rohit
> 
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