求教一道统计学数学题.Suppose X and Y are random variables such that the atandard deviation of X is 2 and the standard deviation of Y is 5.Consider a random variable Z defined as Z=3X-2Y+5.问 a:Assume that X and Y are independtly distribute

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求教一道统计学数学题.Suppose X and Y are random variables such that the atandard deviation of X is 2 and the standard deviation of Y is 5.Consider a random variable Z defined as Z=3X-2Y+5.问 a:Assume that X and Y are independtly distribute
求教一道统计学数学题.
Suppose X and Y are random variables such that the atandard deviation of X is 2 and the standard deviation of Y is 5.Consider a random variable Z defined as Z=3X-2Y+5.问 a:Assume that X and Y are independtly distributed.Find the variance of Z

求教一道统计学数学题.Suppose X and Y are random variables such that the atandard deviation of X is 2 and the standard deviation of Y is 5.Consider a random variable Z defined as Z=3X-2Y+5.问 a:Assume that X and Y are independtly distribute
翻译：
X,Y是两个随机变量,X的标准差为2,Y的标准差为5.设随机变量Z=3X-2Y+5.假设X,Y独立,求Z的方差.
直接用方差的性质求
Var(Z)=3^2*Var(X)+(-2)^2*Var(Y)=9(σY)^2+4(σX)^2=9*(2^2)+4*(5^2)=136

The answer is one,you are welcome

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