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ArandomvariableXhasmeanμ=9andastandarddeviationσ=2.TherandomvariableXismultipliedbytheconstant3tocreateanewvariableY,i.e.,Y=3X.Whatisthevarianceof

题目详情
A random variable X has mean μ = 9 and a standard deviation σ = 2.The random variable X is multiplied by the constant 3 to create a new variable Y,i.e.,Y = 3X.What is the variance of
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答案和解析
3^2 *4=36
standard deviation 这个是标准差 variance 这个是方差 方差=标准差的平方
X的方差是2^2=4
所以 Y的方差是3^2*4=36