7.设X_(1),X_(2),X_(3)是来自总体Xsim N(0,1)的一组样本,则X_(1)+X_(2)+X_(3):____,X_(1)^2+X_(2)^
3.(填空题)3.设X_(1),...,X_(5)是来自总体X的样本,且Xsim N(0,1),则k=____时,kcdot(X_(1)^2+X_(2)^2+X
设(X_(1),X_(2),X_(3),X_(4))是总体X的简单随机样本,X~N(0,4),F=C(X_(1)^2)/(X_(2)^2+X_{3)^2+X_(
X_(8)是来自正态总体Xsim N(0,9)的样本,证明:(X_(1)+X_(2)+X_(3)+X_(4))/(sqrt(X_(5)^2)+X_{6^2+X_
1.设随机变量X_(1),X_(2),X_(3),X_(4)相互独立,服从相同的正态分布N(mu,sigma^2),则Y=(1)/(2sigma)(X_(1)^
1 设总体Xsim N(0,1),X_(1),X_(2),...,X_(n)为X的样本,则((X_(1)-X_(2))/(X_(3)+X_{4)})^2服从__
设X_(1),X_(2),...,X_(n)相互独立,且都服从标准正态分布N(0,1),则sum_(i=1)^nX_(i)^2simchi^2(n-1).A.
设X_(1),X_(2),...,X_(n)为总体Xsim N(mu,sigma^2)的样本,证明hat(mu)_(1)=(1)/(2)X_(1)+(2)/(3
16.设总体Xsim N(0,1),X_(1),X_(2),X_(3),X_(4)是来自总体X的简单随机样本,又设Y=(X_(1)+X_(2))^2+(X_(3
(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