it is urgent, I need the answer please

Let X = (X1 X2 ... Xn) and Y = (Y1 Y2 ... Ym) be two independent random samples and suppose that X, "-"(u, 02) and Y, "" N(u, 2). The sample means from each sample are, X = LizIXi and Y = Em Yi n m Also define two pooled estimators ti ( X , Y ) = n X + my n +m and t 2 ( X , Y ) =; ( X + Y ) . a. Show that both of the pooled estimators ti (X, Y) and t2(X, Y) are unbiased estimators of /. b. Find var(ti (X, Y) ) and var(ti (X, Y)). c. Derive the efficiency of the estimator t2 (X, Y ) relative to ti (X, Y). d. Show that both estimators are consistent estimators of p. e. Which estimator would you prefer? Provide a reason