Hi,
I am using "biplot" (in package "stats") to visualize the
results of some
PCA analyses. When I use scale=0 in the biplot function, it draws X (PC1)
and Y (PC2) axes, with the scales multiplied by sqrt(N), where N is the
sample size. Is there a way to change these scales so that the actual
values of PC1 and PC2 are shown, instead of multiplication by sqrt(n)?
Also, how can I plot the points in biplot with different colors or symbols
corresponding to a grouping variable, instead of sample row number?
Thanks for any suggestions.
Best,
Ravi.
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Ravi Varadhan, Ph.D.
Assistant Professor, The Center on Aging and Health
Division of Geriatric Medicine and Gerontology
Johns Hopkins University
Ph: (410) 502-2619
Fax: (410) 614-9625
Email: rvaradhan@jhmi.edu
Webpage: http://www.jhsph.edu/agingandhealth/People/Faculty/Varadhan.html
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