Chi-square Distribution. The Chi-square distribution is defined by:

f(x) = {1/[2/2 * (/2)]} * [x(/2)-1 * e-x/2]
= 1, 2, ..., 0 < x

where
     is the degrees of freedom
 e      is the base of the natural logarithm, sometimes called Euler's e (2.71...)
    (gamma) is the Gamma function

The above animation shows the shape of the Chi-square distribution as the degrees of freedom increase (1, 2, 5, 10, 25 and 50).
statická ukážka