Dave's Math Tables: chi2-distribution
(Math | Stat | Distributions | chi2-Distributions)

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

f(chi2) = (chi2)^(n/2 - 1) e^(-chi2 / 2 ) 2^(-n/2) / gamma(n/2)
The area within an interval (a, inf) = integral(a to inf) f(chi2) dchi2 = Gamma(n/2, a/2) / Gamma(n/2) (See also Gamma function)