未知题型

随机变量X的平均值为5，标准差也为5，随机变量Y的均值为9，方差为16，则V＝2X+3Y的均值与方差为（）。

A.37，164
B.37，244
C.22，164
D.22，244

【参考答案】

B
x的平均值为5也就是均值为5，其标准差为5则其方差为25，则E（2x+3y）=2E（x）+3E（y）=2×5......

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未知题型

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随机变量X的平均值为5，标准差也为5，随机变量Y的均值为9，方差为16，则V＝2X+3Y的均值与方差为（ ）。

相关考题

随机变量X的平均值为5，标准差也为5，随机变量Y的均值为9，方差为16，则V＝2X+3Y的均值与方差为（）。