设随机变量X与Y相互独立,且D(x)=D(Y)=1,则D(X-Y)=____.

设随机变量X与Y相互独立,且D(x)=D(Y)=1,则D(X-Y)=____.


【正确答案】:

2


【题目解析】:

D(X-Y)=D(X)+D(Y)=2