[R] slightly off-topic re prcomp()

[Berton Gunter]

If you don't get a response:

reproducible example, please.

I suspect that you're looking at numerical analysis artifacts, assuming I
have correctly interpreted you.

-- Bert Gunter
Genentech Non-Clinical Statistics
South San Francisco, CA
 
"The business of the statistician is to catalyze the scientific learning
process."  - George E. P. Box
 
 

> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch 
> [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Laura Quinn
> Sent: Wednesday, February 08, 2006 9:50 AM
> To: r-help at stat.math.ethz.ch
> Subject: [R] slightly off-topic re prcomp()
> 
> Hi,
> 
> I was wondering if anyone could tell me why prcomp() will 
> "Invent" modes
> of variation in a PCA on identical replicates of data? I would have
> expected 50 (or whatever number) of identical replicates to 
> return a null
> score in such an analysis (or at the least, all variables 
> would share the
> same PC score). This is not the case and I was wondering could someone
> point me in the direction of some literature to explain the 
> reason behind
> this?
> 
> Laura Quinn
> Institute of Atmospheric Science
> School of Earth and Environment
> University of Leeds
> Leeds
> LS2 9JT
> 
> tel: +44 113 343 1596
> fax: +44 113 343 6716
> mail: laura at env.leeds.ac.uk
> 
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