grandes-ecoles 2017 QI.B.2

grandes-ecoles · France · centrale-maths1__psi Central limit theorem
Suppose that $X$ admits a second moment. If $u$ and $v$ are two real numbers such that $u < E(X) < v$, determine the limit of the sequence $\left(\pi_{n}\right)_{n \in \mathbb{N}^{*}}$ defined by $$\forall n \in \mathbb{N}^{*}, \quad \pi_{n} = P\left(nu \leqslant S_{n} \leqslant nv\right)$$
Suppose that $X$ admits a second moment. If $u$ and $v$ are two real numbers such that $u < E(X) < v$, determine the limit of the sequence $\left(\pi_{n}\right)_{n \in \mathbb{N}^{*}}$ defined by
$$\forall n \in \mathbb{N}^{*}, \quad \pi_{n} = P\left(nu \leqslant S_{n} \leqslant nv\right)$$