Theorem 9.3.2. \(\chi^2\) statistics.
\begin{equation*}
\mu = r
\end{equation*}
\begin{equation*}
\sigma^2 = 2r
\end{equation*}
\begin{equation*}
\gamma_1 = 2 \sqrt{2/r}
\end{equation*}
\begin{equation*}
\gamma_2 = \frac{12}{r} + 3
\end{equation*}