4.设Xsim N(3,2^2),试求:(1)P(X<5);(2)P(X>9).(已知Phi(1)=0.8413,Phi(2)=0.9772,Phi(3)=0.
3.设X~N(1,4),Phi(0.5)=0.6915,Phi(1.5)=0.9332,则P(|X|>2)为( ).A. 0.2417;B. 0.3753;C.
设随机变量X~N(μ,2),且P(X>3) =0.5,则μ=( )设随机变量X~N(μ,2),且P{X>3}=0.5,则μ=()
5.设随机变量 sim N(1,4) ,已知 Phi (0.5)=0.6915 , Phi (1.5)=0.9332 ,则-|||- |X|lt 2 = __
已知X~N(1,4),计算:P(X<1) = _ ;P(X<2) = _ ;P(2
若Phi(0.5)=0.6915,Phi(1.5)=0.9332,Phi(2.5)=0.9938,设Xsim N(3,4),则X落在(-2, 2)内的概率为A.
设随机变量X~N(2,),且P(2
设 X~N ( 1 , 4 ) ,求P ( 0 < X < 1.5 ) , P ( |X-1|leqslant 2 ) , P ( X > 3 )设X~N(1,
21、设X~N(3,22),求(1).P(2