5. A confidence interval for Poisson variables
Let X1, ..., Xn be i.i.d. Poisson random variables with parameter λ > 0 and denote by Ḙn their empirical average,
Ḙn = 1/n ∑(i=1 to n) Xi.
Find two sequences (an)n≥1 and (bn)n≥1 such that an(Ḙn - bn) converges in distribution to a standard Gaussian random variable Z ~ N(0, 1).