题目
已知随机变量X与Y相互独立,且D(X) =1,D(Y) =2, 则Cov(X,Y) = ________D(2 X-3 Y-5) =_______
已知随机变量X与Y相互独立,且D(X) =1,D(Y) =2, 则Cov(X,Y) = ________D(2 X-3 Y-5) =_______
题目解答
答案
已知D(X) =1,D(Y) =2
则Cov(X,Y) =0
D(aX+bY)=
∴D(2 X-3 Y-5) =17
已知随机变量X与Y相互独立,且D(X) =1,D(Y) =2, 则Cov(X,Y) = ________D(2 X-3 Y-5) =_______
已知D(X) =1,D(Y) =2
则Cov(X,Y) =0
D(aX+bY)=
∴D(2 X-3 Y-5) =17