Z~N(0,1)P {|x-µ|k=1,查表P{Z<1}=0.8413则P{|Z|<1}=1-(1-0.8413)*2=0.6826k=2,3类罩孙拦凯燃似
k=1:p=0.6826;k=2:p=0.9544;k=3:p=0.9974.