Re: [R] weird results w/ prcomp-princomp

From: ronggui <0034058_at_fudan.edu.cn>
Date: Sat 09 Apr 2005 - 02:00:26 EST

R2.0.1
> x<-matrix(rnorm(44*19),nrow=44)
> princomp(x,cor=TRUE,scores=TRUE)
Call:
princomp(x = x, cor = TRUE, scores = TRUE)

Standard deviations:

   Comp.1 Comp.2 Comp.3 Comp.4 Comp.5 Comp.6 Comp.7 Comp.8 1.5874672 1.4652217 1.3088833 1.2339949 1.1697727 1.1402570 1.0774402 1.0458567

   Comp.9 Comp.10 Comp.11 Comp.12 Comp.13 Comp.14 Comp.15 Comp.16 1.0152164 0.9403912 0.8854087 0.8433314 0.7918201 0.7454395 0.6680463 0.6240805   Comp.17 Comp.18 Comp.19
0.5752994 0.4873633 0.4205193

 19 variables and 44 observations.
> sum(princomp(x,cor=TRUE,scores=TRUE)$sdev^2)
[1] 19

it seems ok.
On Fri, 08 Apr 2005 11:12:26 +0200
Alessandro Bigi <abigi@agrsci.unibo.it> wrote:

> I am doing a Principal Component Analaysis (PCA) on a 44x19 matrix.
> with
> > princomp(x,cor=TRUE,scores=TRUE)
> and
> > prcomp(x,scale=TRUE,center=TRUE)
> The resulted eigenv. and rotated matrix are the same (as expected), however
> the sum of eigenvalues is lower than 19 (number of variables).
>
> With a commercial stat software it worked correctly, with the same dataset.
> Am I doing something wrong?
> Thanks
> Alex
>
>
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https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Sat Apr 09 02:47:54 2005

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