Consider the multiple regression model y, = a + lxlt + 2112, + ut, t =1,2,...,T. (1) Suppose Var(u,) = 62x21 and 3:2: > 0. What are the consequences of this problem on the OLS estimates? Suggest one method to handle this problem. Be as specific as possible. (2) Suppose ut=xiut_l+t, where gt~IN(O,0':) and 7t is known. What are the consequences of this problem on the OLS estimates? Suggest one method to handle this problem. Be as specific as possible