Math2.org Math Tables: chi^2-distributions

(Math)

chi-distributions
The chi2-distribution, with n degrees of freedom, is given by the equation:

\[ f(\chi^2) = (\chi^2)<sup>-1</sup> \exp(-\frac{1}{2}\chi^2) 2<sup>{2}</sup> \frac{1}{\Gamma(\frac{n}{2})} \]
The area within an interval (a, inf) is \[ \int_a^\infty f(\chi^2) \, d\chi^2 = \frac{\Gamma(\frac{n}{2}, \frac{a}{2})}{\Gamma(\frac{n}{2})} \] (See also Gamma function)