题目
(4)设总体 sim N(mu ,1) ,其中μ为未知参数,X1,X2,X3为-|||-来自总体X的样本,下面4个关于μ的估计量中,最好的一个-|||-是 () .-|||-A. dfrac (1)(5)(X)_(1)+dfrac (2)(5)(X)_(2)+dfrac (2)(5)(X)_(3) . B. dfrac (1)(4)(X)_(1)+dfrac (1)(2)(X)_(2)+dfrac (1)(4)(X)_(3)-|||-C. dfrac (1)(6)(X)_(1)+dfrac (5)(6)(X)_(2) D. dfrac (1)(3)(X)_(1)+dfrac (1)(3)(X)_(2)+dfrac (1)(3)(X)_(3)
题目解答
答案
D. $\dfrac {1}{3}{X}_{1}+\dfrac {1}{3}{X}_{2}+\dfrac {1}{3}{X}_{3}$