[R] Limited number of principal components in PCA

[William Armstrong]

David and Josh,

Thank you for the suggestions.  I have attached a file ('q_values.txt') that
contains the values of the 'Q' variable.

David -- I am attempting an 'S' mode PCA, where the columns are actually the
cases (different stream gaging stations) and the rows are the variables (the
maximum flow at each station for a given year).  I think the format you are
referring to is 'R' mode, but I was under the impression that R (the
program, not the PCA mode) could handle the analyses in either format.  Am I
mistaken?

My first eigenvalue is:

> unrotated_pca_q$sdev[1]^2
[1] 17.77812

Does that value seem large enough to explain the reduction in principal
components from 65 to 54?

Also, the loadings on the first PC are not particularly high:

 > max(abs(unrotated_pca_q$rotation[1:84]))
[1] 0.1794776

Does that suggest that maybe the data are not very highly correlated?

Thank you both very much for your help.

Billy

http://r.789695.n4.nabble.com/file/n3719440/q_values.txt q_values.txt 

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