P(ξ=0)=0.38
P(ξ=2)=0.5
P(ξ=4)=0.12
所以ξ的分布列表是
0 2 4
0.38 0.5 0.12
eξ= 0×0.38+2×0.5+4×0.12 = 1.48
(2)解:由於數列an=n2-6/5ξn+1(n∈N*)是嚴格單調的,所以數列3/5 < ξ < 3/2,
即ξ < 5/2
P(A)= P(ξ< 5/2)= P(ξ= 0)+P(ξ= 2)= 0.88