SOA #87

[DonUno]

The central limit theorem states that you can approximate normal distribution with mean - nμ and standard deviation σ*sqrt(n). How come in #87 we use the normal distribution with parameters σ/sqrt(n)...I think I'm missing something valuable, can anyone help?

Unless it is because we are taking the mean?

[Kaner3339]

what you are missing is that it's an average. So Var((X1 + X2 + ...)/n) is n*sigma/n squared. so the STD of it is the root of that.