The $\chi ^2$ distribution

• The $\chi ^2$ distribution is a theoretical probability distribution like the normal distribution, taking one parameter for degrees-of-freedom.

• It's non-symmetrical and starts at zero.

• The higher the degrees of freedom the flatter and more rightward the distribution.

  $\parbox{\textwidth}{\centerline{\large The $\chi^2$ distribution} \includegraphics{chi-dens.eps} \par \centerline{Degrees of freedom: 4, 7 and 11}}$