1.设 approx N(2,18), 若 Y=(B) ),则 approx N(0,1).-|||-(A) dfrac (x-2)(18): (B) dfra
设X与Y相互独立,且approx N(1,2), _(Delta )N(0,1),令approx N(1,2), _(Delta )N(0,1),则D(Z) =
[题目]设 approx N(0,1) backsim N(1,1), 且X,Y是相-|||-互独立的,则 () 。-|||-
13.设随机变量X与Y相互独立,且 approx N(1,2) approx N(0,1), 令随机变量 =2x-Y+3,-|||-则 Z~ __
1.-|||-设 approx N(0,1), 则 =3x-1 服从 ()-|||-A approx N(0,1)-|||-__-|||-B approx N(
(填空题)设 approx N(0,1), 则 =2x+1 的概率密度 _(Y)(y)=() 。(填空题)
2.设随机变量X~N(0,1),令Y=-2X-2,则Y~( ).A. N(-2,-4)B. N(0,1)C. N(-2,4)D. N(2,4)
1.-|||-设 approx N(0,1), 则 =3x-1 服从 ()-|||-A backsim N(0,1)-|||-B approx N(-1,10)
3.设 approx N(0,(4)^2), approx N(1,(3)^2), 且 (rho )_(x)=-dfrac (1)(2), 令 =dfrac (
设随机变量X~N(0,1),Y~N(0,1),则X+Y()A. 服从正态分布N(0,1)B. 服从正态分布N(0,2)C. $$ 服从正态分布N(0, \sqr