(4)设(X1,X2,···,X66)是来自总体 approx N(0,(sigma )^2) 的样本,则 () ~-|||-F(2,4).-|||-(A) dfrac (2({{X)_(1)}^2+({X)_(2)}^2)}({{{_{{{r)_(3)}^2+({X)_(4)}^2+({X)_(5)}^2+({X)_(6)}^2} (B) dfrac ({{X)_(1)}^2-({X)_(2)}^2}({{X)_(3)}^2+({X)_(4)}^2+({X)_(5)}^2+({X)_(6)}^2}-|||-(C) dfrac ({{X)_(3)}^2+({X)_(4)}^2+({X)_(5)}^2+({X)_(6)}^2}({{X)_(1)}^2+({X)_(2)}^2} (D) dfrac (2({{X)_(1)}^2+({X)_(2)}^2+({X)_(3)}^2+({X)_(4)}^2)}({{X)_(1)}^2+({X)_(2)}^2}

(2)设样本X1,X2,···,X5来自总体N (0,1), =dfrac (C({X)_(1)+(X)_(2))}({({{X)_(3)}^2+({X)_(4

(2)设样本X1,X2,···,X5来自总体N (0,1), =dfrac (C({X)_(1)+(X)_(2))}({({{X)_(3)}^2+({X)_(4

4.设总体 sim N(mu ,(sigma )^2), x1,x2,x3为来自X的样本 hat (mu )=dfrac (1)(4)(x)_(1)+b(x)_

3.设总体 approx N(mu ,(sigma )^2), X1,X2···Xn是来自该总体的简单随机样本,则-|||-dfrac (1)({sigma )

设X1,X2,···X16为来自总体 sim N(2,(sigma )^2)设X1,X2,···X16为来自总体 sim N(2,(sigma )^2)（

4.第六章4(1),设样本x1,x2 x1,x4,x4,x,来自总体N(0,1), =(({x)_(2)+(x)_(2)+(x)_(2))}^2+(({x)_(

设总体X服从正态分布N(2,4) ,X1,X2 10,是来自总体X的一个简单样本,则X1,X2 10 ____，X1,X2 10____，X1,X2 10___

1.设X1,X2,···,xn来自总体X的样本, (X)=(sigma )^2, overline (X)=dfrac (1)(n)sum _(i=1)^n(X

4.设总体 sim N(mu ,(sigma )^2) ,(X1,X2,···,Xn)为来自总体X的一个样本,X为样本均-|||-值,则 ()-|||-(A)

设X1,X2,···,Xn是来自总体N(1,4)的样本,设X1,X2,···,Xn是来自总体N(1,4)的样本,