scores plot for PCA

[#1]

The scores plot has a circle inside the scatterplot.  Does this represent a confidence interval or is it more for decorative purposes?  If the former, can the confidence interval be changed?

[#2]

Hi,

I believe that you are referring to the Loading Plot, where the circle represents the maximum possible contribution of each variable (i.e., Distance from zero = 1). The length of the vectors (arrows) represents the relative contribution of each variable to the principal components displayed.

Best,

TS