Question

求概率统计大神设随机变量X服从参数为λ的泊松分布,求E（X+1）^-1

Answer 1

lim n->无穷

Σ(x=0~n)e^-λ(λ^x/x!(x+1))

=[(e^-λ)/λ]{Σ(x=0~n)λ^(x+1)/(x+1)!}

={(e^-λ)/λ}(e^λ -1)

={1-e^(-λ)}/λ