function [stat,asc] = contgd(X,sig)
// 2x2 contingency
// X ... data marix of absolute frequencies
// sig ... significance level of association (default 0.05)
// asc ... association coefficient
// stat ... chi-square computed stat. and quantil [computed tabulated]
// Author: Lukáš Malec
// Date: $2015-12-19$
