Approximating Binomial with Normal
According to the Central Limit Theorem, the normal
distribution can be used as an approximation to the binomial distribution, if the sample size is
large enough.
If X is Binomial (n, p):
$$E(X) = np$$
$$Var(V) = np(1-p)$$
The approximate equivalent normal distribution is N[np,√(np(1-p))], provided
np≥ 5 and n(1- p)≥ 5 (thumb rule).
