what is standardization in pca why is pca important what is difference between correlation matrix and correlation matrix why pca in compositional data is standardization necessary for a pca why is a correlation matrix used in a pca what is the standardization of a correlation matrix should ppca be used for compositional data what is the difference between pca analysis and correlation analysis how to standardize pca data how to standardize pca what is the pca matrix vs a correlation matrix what is the difference between a correlation matrix and a covariance matrix? what to standardize during a composition analysis what is pca standardization why use pca what's the difference between a correlation matrix and a covariance matrix how to conduct standardized data which is more common for pca data and how can it be used? what is the purpose for a pca analysis