7-18. Suppose that a random variable Z is N(0, 1). (1) Demonstrate that E(Z) = 0,V(Z) = 1 using (7.13). (2) Suppose Z is not N(0, 1) but, instead, is a continuous random variable with σ > 0. For Z = X−μ

σ , does E(Z) = 0,V(Z) = 1 still hold? Verify your answer.