weird results w/ prcomp-princomp
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 at 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 -- No virus found in this outgoing message. Checked by AVG Anti-Virus. -- No virus found in this outgoing message. Checked by AVG Anti-Virus.
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