=+13.13. Show that, in the balanced case (i.e., Di = D, 1 ≤ i ≤ m), the P-R, REML, and F-H estimators of A in the Fay–Herriot model are identical

(provided that the estimator is nonnegative), whereas the ML estimator is different, although the difference is expected to be small when m is large.