[R] quadratic discriminant analysis ?
Daniel.Amorese at geos.unicaen.fr
Fri May 17 11:19:27 CEST 2002
Le 2002.05.17 10:08, ripley at stats.ox.ac.uk a écrit :
> On Fri, 17 May 2002, [ISO-8859-1] Daniel Amorèse wrote:
> > Hello,
> > I am a beginner in R and data analysis.
> > I have the VR (MASS) library installed and "Modern Applied
> > with S-Plus" is my bedside book.
> > Could anybody provide me an R script (or pieces of an R script) to
> > a
> > stepwise quadratic discriminant analysis ?
> That needs distribution theory not implemented in R (to my knowledge).
> QDA is rather dependent on multivariate normality, and the stepwise
> variants are even more so. It seems to be very rarely appropriate.
> When I wanted an example, a student ran one for me in what I recalled was
> SPSS under VMS (and it looks like SPSS output), but last time I looked I
> could not see it on the PC version.
> Brian D. Ripley, ripley at 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 272860 (secr)
> Oxford OX1 3TG, UK Fax: +44 1865 272595
> r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
> Send "info", "help", or "[un]subscribe"
> (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch
Thanks for this answer.
Many people claim LDA and QDA are quite robust methods with regard to
Of course, this assertion is certainly not true when a stepwise analysis is
Especially if the stepwise analysis involves Wilks' lambda (this test
Thus, how is it possible to (reliably) select variables when performing qda
or lda through R ?
Lab. M2C "Morphodynamique Continentale et Côtière"
UMR CNRS 6143 Caen/Rouen
Centre de Géomorphologie
UCBN (Université de Caen Basse-Normandie)
14032 Caen Cedex
Ph: +33 (0)2 31 56 57 19
Fax: +33 (0)2 31 56 57 57
Courriel: amorese at geos.unicaen.fr
r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
Send "info", "help", or "[un]subscribe"
(in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch
More information about the R-help