【单选题】设随机变量 X~B(3, 0.4) , , 则 P(Y=1) 的值为
【单选题】设离散型随机变量X的可能取值为x 1 =1,x 2 =2,x 3 =3,且E(X)=2.3,E(X 2 )=5.9,则x 1 ,x 2 ,x 3 所对应的概率为( )
A.
p 1 =0.1,p 2 =002,p 3 =0.7
B.
p 1 =0.2,p 2 =0.3,P 3 =0.5
C.
P 1 =0.3,P 2 =0.5,P 3 =0.2
D.
P 1 =0.2,P 2 =0.5,P 3 =0.3
【单选题】设随机变量 X~B(3, 0.4) , , 则 P(Y=1) 的值为