设随机变量X~N(1,σ^2),且P(0

问题描述:

设随机变量X~N(1,σ^2),且P(00)=

P(0Φ(1)=0.8
Φ(-1)=2*0.8-1=0.4
P(X>0)
=P((x-1)/σ>-1)
=1-Φ(-1)
=0.6