Pearson product moment correlation between y and x
y (Var | NDVar) – First variable.
x (Var | NDVar) – Second variable. Needs to have same type/shape as y.
sub (index) – Use only a subset of the data
ds (Dataset) – If a Dataset is given, all data-objects can be specified as names of
r (float) – Pearson correlation coefficient.
p (float) – Two-tailed p-value.
df (int) – Degrees of freedom.