Re: [R] Help: lda predict

From: Shengzhe Wu <r.shengzhe_at_gmail.com>
Date: Fri 26 Aug 2005 - 23:31:36 EST

I compared "posterior" of these three prediction results, they are a little different.

The book you mentioned should be "Modern Applied Statistics with S. 4th edition". But this book has been borrowed out from our univeristy library by someone else, and I have checked the book "Pattern Recognition and Neural Networks" which does not mention these three lda prediction methods.

Thanks you,
Shengzhe

On 8/26/05, Prof Brian Ripley <ripley@stats.ox.ac.uk> wrote:
> On Fri, 26 Aug 2005, Shengzhe Wu wrote:
>
> > Thanks for your reply. Actually I called function as below.
> >
> > p1 = predict(object, newdata, dimen=1)
> > p2 = predict(object, newdata, dimen=1, method=debiased)
> > p3 = predict(object, newdata, dimen=1, method="predictive")
>
> So why did you say something different?
>
> > The MAP classification of prediction results by any method are the
> > same. I know what the method "plug-in" and "debiased" mean, but what
> > does the "vague prior" for the method "predictive" mean? what is
> > "vague" here?
>
> Please do as we ask, and read the book for which this is supporting
> material (on p.339, to save you looking in the index).
>
> >
> > Thank you,
> > Shengzhe
> >
> >
> >
> > On 8/26/05, Prof Brian Ripley <ripley@stats.ox.ac.uk> wrote:
> >> On Fri, 26 Aug 2005, Shengzhe Wu wrote:
> >>
> >>> I use lda (package: MASS) to obtain a lda object, then want to employ
> >>> this object to do the prediction for the new data like below:
> >>>
> >>> predict(object, newdata, dimen=1, method=c("plug-in", "predictive", "debiased"))
> >>
> >> That is not how you call it: when a character vector is given like that
> >> those are alternatives. Do read the help page, as we ask.
> >>
> >>> What is the exact difference among the three methods? What is the
> >>> difference of prediction results when applying different method?
> >>
> >> This is stated on the help page. If you are unfamiliar with the area,
> >> note that the posting guide points out that MASS is support software for a
> >> book and the explanations are in the book. The help page also has
> >> references: please do read them (before posting).
> >>
> >>> PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
> >>
> >> --
> >> Brian D. Ripley, ripley@stats.ox.ac.uk
> >> Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
> >> University of Oxford, Tel: +44 1865 272861 (self)
> >> 1 South Parks Road, +44 1865 272866 (PA)
> >> Oxford OX1 3TG, UK Fax: +44 1865 272595
> >>
> >
> >
>
> --
> Brian D. Ripley, ripley@stats.ox.ac.uk
> Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
> University of Oxford, Tel: +44 1865 272861 (self)
> 1 South Parks Road, +44 1865 272866 (PA)
> Oxford OX1 3TG, UK Fax: +44 1865 272595
>



R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Fri Aug 26 23:35:50 2005

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