t-distribution

The density function of the $t$-distribution is parameterised by the number of degrees of freedom, $n$, and is given by

$$f(t) = \frac{\Gamma \left[(n + 1)/2\right]}{\sqrt{n\pi}\Gamma(n/2)}\left(1 + \frac{t^2}{n}\right)^{-(n+1)/2}$$ (31)