R help - May 2004 - Factor loadings and principal component plots

Hi- Can anyone tell me the command(s) to produce the following plots:

-Factor loadings plot for principal components
-Plot of principal component scores

Also, apart from the prcomp (or princomp) command is there any other way to
obtain principal components and if so, how does it/they stack up to prcomp?

Thanks in advance for any assistance you can provide.

Neil Desnoyers

Hi Neil,

> -----Mensaje original-----
> De: r-help-bounces at stat.math.ethz.ch
> [mailto:r-help-bounces at stat.math.ethz.ch]En nombre de ndesnoyers at
att.net
> Enviado el: lunes, 03 de mayo de 2004 23:22
> Para: r-help at stat.math.ethz.ch
> Asunto: [R] Factor loadings and principal component plots
> 
> 
> Hi- Can anyone tell me the command(s) to produce the following plots:
> 
> -Factor loadings plot for principal components
> -Plot of principal component scores
Probably you can look directly to the screeplot() or loadings() functions. 
> 
> Also, apart from the prcomp (or princomp) command is there any 
> other way to obtain principal components and if so, how does 
> it/they stack up to prcomp?
 eigen()or svd() functions
> 
> Thanks in advance for any assistance you can provide.
> 
> Neil Desnoyers

Antonio
> 
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Well, factor loadings apply to factor analysis, not PCA, so have you 
confused the two?  (Lots of the literature does.)

On Mon, 3 May 2004 ndesnoyers at att.net wrote:
> Hi- Can anyone tell me the command(s) to produce the following plots:
> 
> -Factor loadings plot for principal components
> -Plot of principal component scores
Easy via the predict and biplot methods: see the examples in the 
MASS/scripts/ch11.R file.
> Also, apart from the prcomp (or princomp) command is there any other way
> to obtain principal components and if so, how does it/they stack up to
> prcomp?
Yes, but princomp is the recommended way, not prcomp.

-- 
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)
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