The chi-squared distribution arises in statistics. If \(Y_i\) are \(n\) independent Gaussian random variates with unit variance then the sum-of-squares,
has a chi-squared distribution with \(n\) degrees of freedom.
This function returns a random variate from chi-squared distribution with nu degrees of freedom. The distribution function is,
for \(x \geq 0\).
This function computes the probability density \(p(x)\) at \(x\) for a chi-squared distribution with nu degrees of freedom, using the formula given above.
These functions compute the cumulative distribution functions \(P(x), Q(x)\) and their inverses for the chi-squared distribution with nu degrees of freedom.