一个关于概率的话题

p(X & gt；96)= P((X-μ)/σ& gt；(96-72)/σ)= 2.3%-& gt；p((X-μ)/σ& lt；24/σ)=1-2.3%=0.977

查表，24/σ= 1.885->σ= 12.732

60到72之间的概率= p (60

= P((60-72)/σ& lt；(X-72)/σ& lt；0)= P(-0.9425 & lt；(X-72)/σ& lt；0)=Φ(0)-Φ(-0.9425)

=Φ(0)-1+Φ(0.9425)=0.5-1+0.8264=0.3264=32.6%,

60到84分之间的概率= 2p (60