Problem 3. (10 points) Roll a fair six-sided die once and observe X, the number of dots facing up. 1. What is the probability mass function (PMF) of random variable X? (3 points) 2. What is the cumulative distribution function (CDF) Fx(x) of random variable X? (3 points) 3. What is E[X2], the expected value of X? (2 points) 4. What is Var[X], the variance of X? (2 points)