Let S =
XTX be the sample covariance matrix where L and P are latent roots and vectors of XTX respectively. Prove that S has latent root
and latent vectors P. Using this result show that correlation loadings of S are given by
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where si is the ith diagonal element of S, and consequently correlation loadings are the same for both XTX and S. Show also that XTX and S possess the same standardized PC scores, but that unstandardized scores differ.