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)^2B.sim (X)^2(3) =(X)^2C.sim (X)^2(3) =(X)^2D.sim (X)^2(3) =(X)^2

设随机变量X，Y独立，且sim ({X)_(m)}^2，sim ({X)_(m)}^2，令sim ({X)_(m)}^2，则sim ({X)_(m)}^2服从_

设随机变量 X sim N(2, 4), Y sim N(1, 1), 且 X, Y 相互独立, 则 Z = X - 2Y + 3 sim ( )A. $N(7

设随机变量 X sim N(1, 2), Y sim N(-1, 2), Z sim N(0, 9)。且随机变量 X, Y, Z 相互独立, 已知 a(X +

21.已知随机变量X1 ,X2,X3相互独立,且 _(1)sim U(0,6), _(2)sim N(1,3), _(3)sim EXP(3) 求Y-|||-=

设随机变量sim P(2)则 E ( X ) =_______, D ( X ) =__________ ,sim P(2)________.设随机变量则E(X

若随机变量 X sim N(0,1)，则 Y = 3X - 2 simA. $N(-4,3)$B. $N(-4,3^2)$C. $N(-2,3)$D. $N(-

9、若随机变量 sim N(-2,4) , sim N(3,9) ,且X与Y相互独立。设 =2x-y+5 ,则 sim N(-2,25) ___

设随机变量 X,Y 相互独立，且 X sim N(mu_1, sigma^2), Y sim N(mu_2, sigma^2), 则 X-Y 为( ) 设随机变

(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

设X1、X2、X3是3个随机变量,且 _(1)sim N(0,1) , _(2)sim N((0,{2)^2}) , _(3)sim N((0,{3)^2)}