Calculate the scalar delta.
This parameter comes from the optimal Spearman<U+2019>s correlation
when the rank of two vectors X and proba are equal except on a given set of indices.
In our context, this set correspond to the zero-values of the vector proba.
Usage
delta(X, proba)
Arguments
X
a vector.
proba
a zero-inflated proportions response.
Value
Delta the scalar Delta calculated for the vector x
and the vector proba.