设随机变量X与Y的方差均存在且不为0,若E(XY)=EXEY,则( ).A.X与Y一定独立B.X与Y一定不相关C.D(XY)=DXDYD.D(X-Y)=DX-DY
5.对于任意两个随机变量X和Y,若E(XY)=E(X)E(Y),则有A.X和Y独立B.X和Y不独立C.D(X+Y)=D(X)+D(Y)D.D(XY)=D(X)D(Y)满分:5 分6.设a=1,b=2,EX=3,则E(a+bX)=A.1B.2C.6D.7满分:5 分7.A.N(0,5) B.N(5,5) C.N(5,25) D.N(5,1) 满分:5 分8.两个随机变量不...