设X sim N(0,1),Phi(x) = (1)/(sqrt(2pi)) int_(-infty)^x e^-(t^2)/(2) dt,(x geq 0),
设随机变量 X 服从均值为 10,均方差为 0.02 的正态分布.已 知(x)=(int )_(-infty )^xdfrac (1)(sqrt {2pi )}
设随机变量X的分布函数为(X)=dfrac (1)(2)Phi (x)+dfrac (1)(2)Phi (dfrac (x-4)(2))(X)=dfrac (1
8.[判断题]•标准正态分布Phi(x)=int_(-infty)^xvarphi(t)dt=(1)/(sqrt(2pi))int_(-infty)^xe^-(
设随机变量X的概率密度为 (x)=dfrac (1)(2sqrt {2pi )}(e)^-dfrac ({(x-3)^2)(8)}(-infty lt xlt
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 = __
若随机变量 X sim N(0,1) ,Phi(x)为其分布函数,则 Phi(x)+ Phi(-x)= ()。A. -1B. 0C. 1D. 2
15.设随机变量X的概率密度为-|||-(x)=dfrac (1)(sqrt {pi )}(e)^-(x^2+2x-1), -infty lt xlt +inf
5、已知随机变量X的密度函数为 (x)=dfrac (1)(2sqrt {2pi )}(e)^-dfrac ({(x-1)^2)(8)}, 则 =dfrac (
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.