what does the length of arrows represent in the correlation circle plot in pca analysis?

Question

I want to know that in PCA analysis or FAMD the lengths of arrows in correlation circle plot(which can be plotted by bellow code) is equal to which parameter(coefficient estimates,cos2,contribution,...) while their coordinates represent their loadings?

 fviz_pca_var(res.pca)

res.pca is the result of fitting PCA analysis on our data. Any help would be greatly appreciated.

Would you kindly add the plot you are talking about to this question? — Nikolas Rieble, Aug 28 '17 at 13:02
Search `pca arrows biplot` and `pca loading plot`. This has been described many times on CV. — ttnphns, Aug 29 '17 at 07:39

score -1 · Answer 1 · answered Aug 29 '17 at 08:52

-1

The length of the an arrow represents how well the parameter explains the distribution of the data. A parameter with an arrow that is clearly longer than others has a better correlation.

In your case, most arrows have a similar length, so the parameters contribute equally.

answered Aug 29 '17 at 08:52

ecotopic

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`A parameter with an arrow that is clearly longer than others has a better correlation` That is unclear and possibly wrong. `the parameter explains the distribution of the data` that too. – ttnphns Aug 29 '17 at 11:00
Perhaps supplementing this with a more quantitative explanation would help. – Scortchi - Reinstate Monica Aug 29 '17 at 11:27

what does the length of arrows represent in the correlation circle plot in pca analysis?

1 Answers1