Bhattacharyya angle
In statistics, Bhattacharyya angle, also called statistical angle, is a measure of distance between two probability measures defined on a finite probability space. It is defined as Δ ( p , q ) = arccos BC ( p , q ) {\displaystyle \Delta (p,q)=\arccos \operatorname {BC} (p,q)} where pi, qi are the probabilities assigned to the point i, for i = 1, ..., n, and BC ( p , q ) = ∑ i = 1 n p i q i {\displaystyle \operatorname {BC} (p,q)=\sum _{i=1}^{n}{\sqrt {p_{i}q_{i}}}} is the Bhattacharya coefficient.