Class StudentDistribution

Probability density function for $n$ degrees of freedom (see http://mathworld.wolfram.com or http://wikipedia.org): $$ f(x) = \frac {\Gamma\left(\frac{n+1}{2}\right)} {\sqrt{n\pi} , \Gamma\left(\frac{n}{2}\right)}: \frac {1} {\left(1+\frac{x^2}{n}\right)^{(n+1)/2}} $$