26.设 sim N(1,4), (1)求 (0lt Xlt 5); (2)求 (|X|gt 2); (3)设c满足 (Xgt -|||-)geqslant 0.95, 问c至多为多少?

4.设 sim N(3,(2)^2) ,求(1) (2lt Xlt 5) ,(|X|geqslant 2) :(2)设d满足 (Xgt d)geqslant 0

26、设 sim N(3,(2)^2)-|||-(1)求 2lt xleqslant 5 , -4lt Xleqslant 10 , |x|gt 2

12.设 sim N((3,2)^2) ,试求:-|||-(1) (2lt Xleqslant 5) ,(-4lt Xleqslant 10) , (|X|ge

设X～N(3,22),(1)求P(2＜X≤5),P(|X|＞2),P(X＞3);(2)确定c，使得P(X＞c)=P(X≤c)；(3)设d满足P(X＞d)≥0.9

2.设 sim N(2,4) ,试求:-|||-(1) Xgt 1 ;-|||-(2) |X-1|gt 1 .

19.7设 sim N(0,1),-|||-(1)求 X=0 , Xleqslant -1.25 |X|gt 0.68 ;-|||-(2)求λ,使它满

[问答题]设X～N（1，4）总体，求P{0≤X≤2

14.设随机变量X服从正态分布 (-2,9), 求:-|||-(1) Xgt -1 ;-|||-(2) -5leqslant Xleqslant 3 ;

1.填空题-|||-设随机变量 sim N(2,(sigma )^2) ,已知-|||-(0lt xlt 2)=0.4 ,则 (Xgt 0)= () ,-|||

设 sim N(0,1) ,求:(1) =(X)^2;