Question

已知ξ～N(0,)且P(-2<ξ<0)=0.4,則P(ξ>2)="(    "   )

A．0.1

B．0.2

C．0.3

D．0.4

Answer 1

A

由P(ξ>2)+ P(0<ξ<2)+ P(-2<ξ<0)+ P(ξ<-2)=1，
又P(ξ>2)= P(ξ<-2), P(0<ξ<2)= P(-2<ξ<0),所以P(ξ>2)=[1-2P(-2<ξ<0)]=0.1。