1. An urn contains 3 red balls and 5 black balls. They are withdrawn from the urn, one at a time and without replacement. Number the red balls from 1 to 3. Define 1, if Red Ball-i is removed before any black ball is chosen, Xi = 0, otherwise for i = 1, 2,3. Let S be the number of red balls removed before the first black ball is chosen. Then S = Cl Xi. (a) Calculate: E(X;), Cov(X;, X;) for i # j and E(S), Var(S)