Suppose X has a standard normal distribution. The pnorm(), dnorm(), and qnorm() functions should be useful in the following. Remember, ifX has a standard normal distribution then E(X) = 0 and Var(X)=1. a) What is the expected value of 3.5X +7 ? 4.7 3'5X+7 .7 7 b) What is the variance of 2 c) Using R, find the expected value of (X7? ? d) Using R, calculate the probability X > 1.77) e) Using R, calculate the probability that -1.58