Loi normale

$X=\mathcal{N}(\mu,\ \sigma)$

$$\forall x \in \mathbb{R}, \qquad f(x)=\frac{1}{\sigma \sqrt{2 \pi}} \exp^{- \frac{(x- \mu )^2}{2 \sigma ^2}}$$

$$E(X)=\mu$$    et $$\qquad V(X)=\sigma ^2$$