Question

Given X ~ B (n, p)
If n = 10 and p = 0.4, find E(X) and var (X).

Answer 1

Given, n = 10, p = 0.4
q = 1 – p = 1 – 0.4 = 0.6
Now, E(X) = np = 10 x 0.4 = 4 
Var(X) = npq = 10 x 0.4 x 0.6 = 2.4