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随机变量X,Y的方差分别为4和1,相关系数为0.1,则随机变量3X+2Y的方差为多少?
随机变量X,Y的方差分别为4和1,相关系数为0.1,则随机变量3X+2Y的方差为多少?
发布时间:2021-02-28 05:22:07
随机变量X,Y的方差分别为4和1,相关系数为0.1,则随机变量3X+2Y的方差为多少?
网友回答
D(3X+2Y)=9D(X)+4D(Y)+12Cov(X,Y)
Cov(X,Y)=0.1*根号D(X)*根号D(Y)
随机变量3X+2Y的方差为42.4
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设随机变量(X,Y)的方差D(X)=4,D(Y)=1,相关系数ρXY=0.6,则方差D(3X-2Y)
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设两个相互独立的随机变量X和Y的方差分别为4和2,则随机变量3X-2Y的方差是( )A. 8B.
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