(B) ({S)_(x)}^2+({S)_(Y)}^2sim ({x)_(x)}^2(2n-2).-|||-(C) dfrac (overrightarrow
(B) (n-1)(S)^2+(overline {X)}^2 (C) (S)^2+(overline {X)}^2. (D) dfrac (n-1)(n)(S
({x)_(n)}^2服从自由度为m的({x)_(1)}^2=({x)_(1)}^2+({x)_(2)}^2+... ({x)_(n)}^2分布,则({x)_(
A)(S^2)/(sigma^2) sim chi^2(n-1) B)(n(overline(X)-mu)^2)/(S^2) sim F(1, n-1)
=dfrac (1)({X)^2}, 则()-|||-A、 sim (chi )^2(n) B、 sim (chi )^2(n-1) C、 sim F(n,1)
(3)设X_(1)sim N(1,2),X_(2)sim N(0,3),X_(3)sim N(2,1),且X_(1),X_(2),X_(3)相互独立,则P0le
10.设总体 sim N(0,1), X1,X2,X3是来自X的样本,则 =dfrac (sqrt {3)X}(sqrt {{{X)_(1)}^2+({X)_(
若_(i)sim N(0,1), =1,2,(X)_(1),(X)_(2)独立,则_(i)sim N(0,1), =1,2,(X)_(1),(X)_(2)()A
6、设X_(1)sim N(1,2),X_(2)sim N(0,3),X_(3)sim N(2,1),且X_(1),X_(2),X_(3)独立,则P(0le 2
总体 X 与 Y 相互独立,且 X sim N(mu_1, sigma^2),Y sim N(mu_2, sigma^2),(X_1, X_2, ..., X_