设随机变量X~N(2,4),则P{X≤0}= 附∮(1)=0.8413

问题描述:

设随机变量X~N(2,4),则P{X≤0}= 附∮(1)=0.8413

设Z=(X-2)/2
则,N(0,1)
P(X≤0)=P(Z≤-1)
=Φ(-1)
=1-Φ(1)
=1-0.8413
=0.1587