Hi All,

How about the output of summary

pca <- prcomp(USArrests, scale = TRUE)
summary(pca)

Good luck,
steve

On Mon, Oct 18, 2010 at 5:53 AM, Gerhard Thallinger <
Gerhard.Thallinger@tugraz.at> wrote:

> Dear John,
>
> > Please help me out with this regard. 'prcomp' provides Standard
> > deviation, Proportion of variance and Cumulative Proportion. How to
> > use them in calculating the percentage of variance at all three
> > PC level.
>
>  The percentage of variance explained can be calculated as follows:
>
>    pca <- prcomp(USArrests, scale = TRUE)
>    pc1 <- round(pca$sdev[1]^2/sum(pca$sdev^2)*100,2)
>    pc2 <- round(pca$sdev[2]^2/sum(pca$sdev^2)*100,2)
>    etc ...
>
> Hth
>
> Gerhard
>
> ------------------------------------------------------------------------
> Dr. Gerhard Thallinger             E-mail:  Gerhard.Thallinger@tugraz.at
> Institute for Genomics and Bioinformatics   Web: http://genome.tugraz.at
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