设随机变量
相互独立，
，令
，则
.
A.48
B.36
C.55
D.16
设随机变量相互独立，，令，则.
A.48
B.36
C.55
D.16
设X1,X2是相互独立的随机变量,则 (2(X)_(1)+(X)_(2))=( )设X1,X2是相互独立的随机变量,则 (2(X)_(1)+(X)_(2))=
设随机变量_(1),(X)_(2),(X)_(3)是来自正态总体_(1),(X)_(2),(X)_(3)的样本，则当_(1),(X)_(2),(X)_(3)时，
已知随机变量X1,X 2,X3的协方差 ((X)_(1),(X)_(3))=2 ,_(00)((X)_(2),(X)_(3))=1 ,则 _(00)((X)_(
设随机变量x1,x2,x 3,x4相互独立,且有 ((x)_(i))=i,-|||-((x)_(i))=5-i;i=1,2,3,4, 设-|||-=2(x)_(
5.设随机变量X1,X2,X3相互独立,且都服从区间[0,a]上均匀分布,令-|||-=max {x)_(1),(x)_(2),(x)_(3)} , =min
设X为随机变量,且E(X)=-1,D(X)=3,则E(3(X^2-2))=_____.设$$X$$为随机变量,且$$E(X)=-1,D(X)=3$$,则$$E(
(7)设X为随机变量,且 E(X)=-1 ,D(X)=3 ,则 (2(X)^2-3)= __ .
设sim (X)^2(3) =(X)^2且X,Y相互独立,则称随机变量sim (X)^2(3) =(X)^2 ( ) A.sim (X)^2(3) =(X)^2
22.(1)设随机变量X 1,X2,X3,X4相互独立,且有 ((X)_(i))=i ,((X)_(i))=5-i i=1 ,2,3,4.设 Y=-|||-.(
已知随机变量X_(1), X_(2), X_(3)的协方差COV(X_(1), X_(3)) = 2, COV(X_(2), X_(3)) = 1。则COV(X