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](/uploads/image/z/12476321-17-1.jpg?t=%E6%B1%82%E6%95%99%E4%B8%80%E9%81%93%E7%BB%9F%E8%AE%A1%E5%AD%A6%E6%95%B0%E5%AD%A6%E9%A2%98.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%3D3X-2Y%2B5.%E9%97%AE+a%3AAssume+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 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