[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-|||-P .dfrac (1)(3) .dfrac (2)(3)-|||-则下列式子正确的是 () .-|||-(a) X=Y-|||-(b) X=Y-|||-)(c) X=Y =dfrac (5)(9)-|||-(d) X=Y =0

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

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

设随机变量X与Y相互独立， X在区间[ 3 , 9 ] 上服从均匀分布 -1 1-|||-Y~( dfrac (1)(3) 2,那么 D ( 2X-3Y ) =

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 与 Y 相互独立,X N ( 0 ,1 ) ,Y N ( 1 ,1 )(A) P ( X + Y ≤ 0 ) = dfrac (1)(2)

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 (

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)-|

设随机变量X与Y的联合分布律为X/Y 1 2 3-|||-1 1/9 2/9 2/9-|||-2 0 dfrac (1)(9) dfrac (2)(9)-|||

设二维随机变量(X,Y)的分布律为-|||-Y 0 1 2-|||-0 dfrac (1)(4) 0 dfrac (1)(4)-|||-1 0 dfrac (1

16.设X与Y相互独立,其分布列分别为-|||-X -2 -1 0 dfrac (1)(2)-|||-p dfrac (1)(4) dfrac (1)(3) d