A. 16;
B. 32;
C. 1;
D. $\frac{1}{32}$;
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
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_(
例2 设X_(1),X_(2),X_(3),X_(4)为来自正态总体N(0,4)的简单随机样本,记X=a(X_(1)-2X_(2))^2+b(3X_(3)-4X
4.(1)设样本X_(1),X_(2),...,X_(6)来自总体N(0,1),Y=(X_(1)+X_(2)+X_(3))^2+(X_(4)+X_(5)+X_(
设总体 X sim N(mu, sigma^2), X_(1), X_(2), ..., X_(n) 为来自总体X的简单随机样本,则 sum_(i=1)^n((
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__
5、设X_(1),X_(2),X_(3),X_(4)为来自总体X的样本,且EX=mu,记hat(mu)_(1)=(1)/(2)(X_(1)+X_(2)+X_(3
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_
二次型f(x_(1),x_(2),x_(3))=x_(1)^2+4x_(2)^2+4x_(3)^2+2lambda x_(1)x_(2)-2x_(1)x_(3)
5、设总体Xsim N(mu,sigma^2),x_(1),x_(2),x_(3)为来自X的样本,则当常数a=____时,hat(mu)=(1)/(4)x_(1