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

(单选题)设总体sim N(0,1) sim N(2,4),分别从X和Y中随机抽取简单随机样本sim N(0,1) sim N(2,4)和sim N(0,1)

设 sim N(0,1) ,求:(1) =(X)^2;

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

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

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

2.求下列极限：4) lim _(xarrow 1)(dfrac (1)(x-1)-dfrac (2)({x)^2-1});2.求下列极限：

26.设 sim N(1,4), (1)求 (0lt Xlt 5); (2)求 (|X|gt 2); (3)设c满足 (Xgt -|||-)geqslant 0

设随机变量 sim N(1,2) sim N(2,4), 且X与Y相互独立,则 ()A.B.C.D.

设 sim N(0,1) ,求 =2(X)^2+1 的概率密度.

设 X sim N(3, 4)，试求：（1）P(5 < X < 9)；（2）P(X > 7)。（已知 Phi(1) = 0.8413，Phi(2) = 0.97