I am looking at an example of using PCA:
https://wiki.q-researchsoftware.com/wiki/Principal_Components_Analysis_Biplot
Specifically, Example 2 has data
What are the points I'm looking at the biplot? Are those the tips of the projections of the vectors to the plane spanned by the principle axes? Are the lengths of the vectors related to the corresponding eigenvalues of the covariance matrix?
