Letbe a random variable with the following probability distribution
Value x of X / P (X=x)
20 / 0.05
30 / 0.05
40 / 0.35
50 / 0.20
60 / 0.35
Find the expectation of E(X) and variance Var (X) of X.
(A) E (x) = ?
(B) Var (X) = ?