-Wow! This is a marvelous room! You must spend a lot of time and energy in it. -_____________________. 选择一项: A. Great, I am very art-conscious. B. Don.t mention it. C. Thanks you. It really cost me that much.
参考答案:
设x1,x2,x是来自N(u,2)的样本,则E((x-2)=i - 1 A ( n - 1 ) a
设x1,x2,x是来自N(u,2)的样本,则E((x-2)=i - 1 A ( n - 1 ) a 2 Ba 2