13.3 Suppose that in Exercise 13.2 the A- and B-factors are 22 factorials with factors A. A2 and B. B2, respectively. (i) Give expressions for the estimates of the main effects A and A2, and for the interaction AA2. (ii) Give expressions for var(A1), var(A2). var(A A2) and for the estimators of these variances. (iii) Do the same for B1, B2, B1 B2. (iv) Give an expression for the estimator for the interaction A B, its variance, and the estimator for this variance.