题目内容
设离散型随机变量ξ满足Eξ=3,Dξ=1,则E[3(ξ-1)]等于
A.27
B.24
C.9
D.6
A.9 B.6 C.30 D.36
设离散型随机变量满足,,则等于( )
A.27 B.24 C.9 D.6
A.18 B.12 C.20 D.36