I'm confused about the description of the inputs to the pca function between what the variables vs the observations are.
I have 4 vectors, a b c and d. Vectors a b and c contain values for corresponding variables a b and c. Vector d contains values for observations. That is, when a was a(1), then b was b(1), c was c(1), and the observed value was d(1). When a was a(2) then b was b(2), c was c(2), and the observed value was d(2). Etc etc. How do I structure this for the pca function input?