Evaluates the population covariance from the provided full populations. On a dataset of size N will use an N normalizer and would thus be biased if applied to a subset. Returns NaN if data is empty or if any entry is NaN.

Evaluates the population covariance from the provided full populations. On a dataset of size N will use an N normalize and would thus be biased if applied to a subset. Returns NaN if data is empty or if any entry is NaN. Null-entries are ignored.