Suppose that Y1, Y2, Y3 denote a random sample from an exponential distribution with density function f(y) = 1???? e−y/????, 0 < y,0, elsewhere. We determined that 1 = Y1, 2 = (Y1 + Y2)2 , 3 = (Y1 + 2Y2)3 , and 5 = Y are all unbiased estimators for ????. Find the efficiency of 1 relative to 5, of 2 relative to 5, and of 3 relative to 5.