Pick a college student at random. Let X be the person's grade on AP calculus (a number between 1 and 5) and Y their high school calculus grade (A = 4, B = 3 or C = 2). Suppose the following hypothetical table represents the joint probability mass function of (X, Y) (a) Are X and Y independent? Give a mathematical justification for your answer. (b) Calculate Cov(X, Y). For Question 4, calculate the correlation p(X, Y).