设随机变量X的分布律为X -1 0 1-|||-P dfrac (1)(5) dfrac (3)(5) dfrac (1)(5)设X -1 0 1-|||-P dfrac (1)(5) dfrac (3)(5) dfrac (1)(5)，求(1)E(X),D(X);(2)E(Y),D(Y);(3)X -1 0 1-|||-P dfrac (1)(5) dfrac (3)(5) dfrac (1)(5)

已知离散型随机变量X的分布律如下.-|||-x -2 -1 0 1 3-|||-p dfrac (1)(5) dfrac (1)(6) dfrac (1)(5)

设随机变量X和Y的联合分布律为X -1-|||-Y 0 1-|||--1 dfrac (1)(8) dfrac (1)(8) dfrac (1)(8)-|||-

设随机变量X,Y满足P(XY=0) =1,并且分布律分别为X -1 0 2 Y 0 1-|||-P dfrac (1)(6) dfrac (1)(3) dfra

29.设随机变量(X Y)的分布律为-|||-x .-1 0 1-|||-Y-|||--1 dfrac (1)(8) .dfrac (1)(8) dfrac (

[例2]设随机变量X与Y相互独立,其概率分布为-|||-x 0 1-|||-P .dfrac (1)(3) .dfrac (2)(3)-|||-Y 0 1-||

25.设随机变量（X,Y）的分布律为X-|||-Y -1 0 1-|||--1 dfrac (1)(8) dfrac (1)(8) dfrac (1)(8)-|

【题文】设离散型随机变量X的分布列为: X -1 0 1 2 3 P dfrac (1)(10) dfrac

已知随机变量X的分布律为-|||-x 2 3 4 9-|||-p dfrac (1)(8) dfrac (5)(8) dfrac (1)(8) dfrac (1

已知随机变量X1和X2的概率分布为-|||-X1 -1 0 1 X2 0 1-|||-pi dfrac (1)(4) .dfrac (1)(2) dfrac (

2.22 已知离散型随机变量ξ的分布列为-|||-ξ -2 -1 0 1 3-|||-P dfrac (1)(5) dfrac (1)(6) dfrac (1)