Letbe a random variable with the following probability distribution.

Valueof x of X / P(X=x)

3 / 0.05

4 / 0.30

5 / 0.25

6 / 0.10

7 / 0.30

Complete the following. (If necessary, consult a list of formulas.)

(a) Find the expectationof E (X) of X.

E(X) = _______

(b) Find the variance Var (X) of X.

Var(X)=________