[R] princomp

[Peter Ho]

Hi,

In using the princomp function for Principle components analysis does setting

1) cor=TRUE result in princomp using a correlation matrix as in princomp(crimes,
cor = TRUE) and

2)cor=FALSE, a covariance matrix as in princomp(scale(crimes, scale = TRUE, center
= TRUE), cor = FALSE)

The help file explains the difference in scaling, but it is unclear to me if
automatic scaling (cor=TRUE) gives standardisation of data like in the case when
(cor=FALSE)

Rusults using both methods are quite similar though.
Can anyone explain the difference.


Thanks

Peter
-----------------------

Peter Ho
Escola Superior de Biotecnologia
Universidade Católica Portuguesa
Rua Dr. António Bernardino de Almeida
4200 Porto
Portugal
Tel: ++351-2-5580043

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