设随机变量X、Y相互独立,且X~N(μ1,σ21),Y~N(μ2,σ22),
则:(1)E(X+Y)=_____;
(2)D(X+Y)=_____.
设随机变量X、Y相互独立,且X~N(μ1,σ21),Y~N(μ2,σ22),
则:(1)E(X+Y)=_____;
(2)D(X+Y)=_____.
【正确答案】:(1)μ1μ2;(2)σ21σ22
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