Exercise 3 Consider the regression model y; =3 +3 I;+ . The Gauss-Markov conditions hold. Find cov( e; , e; ) using the following two methods: a. Express e; = _L, qY and e; = ", p, Y, and then use the results on handout #1, pages 12-14. b. Find cov( e; , e; ) using cov( e., e;) = cov(Y, -Y,, Y, - Y;) = cov - Y B ( I; - D) , Y - Y B (1; - ])