Re: [R] Help: lda predict

From: Prof Brian Ripley <ripley_at_stats.ox.ac.uk>
Date: Fri 26 Aug 2005 - 23:07:54 EST

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

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Received on Sat Aug 27 03:47:10 2005

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