Rayleigh distribution (EN)

ATTENTION - instead of a decimal comma should be used decimal DOT ! (EN)

**Formulas (EN)**
$P(x)=\left\{\begin{matrix} \frac{x}{\sigma^2} e^{-x^2/2\sigma^2} & ... & x > 0\\ & & \\ 0 & ... & x\leq 0\end{matrix}\right.$
$E(X)=\sigma \sqrt{\frac{\pi}{2}}$	$D(X)=\frac{4 - \pi}{2} \sigma^2$
$\gamma _{1}=\frac{2\sqrt{\pi}(\pi - 3)}{(4-\pi)^{3/2}}$	$\gamma _{2}=-\frac{6\pi^2 - 24\pi +16}{(4-\pi)^2}$