Time series questions

QUESTION 1 Suppose E(X) - 3, Var(X) - 7. E(Y) =0. Var(Y) =9, and Corr(X, Y) = 0.49. Find 1.1 Var ( X 4 )) 1.2 Cov(x- y, x4 ) ) (41 (4] (8 MARKS] QUESTION 2 Consider the ARIMA(1,1) process X =Q1+6, -06, 1. Where a, L WN(0,o? ) Compute: 1. E(x, ) 11. Var (X, ) III. (1- 0,0 ) (4 -0,) IV. Prove that P.= " for * 21 1- 20 0 + 0 [20 MARKS]