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欢欢 · 2021年08月10日

所以任意变量的标准差都是≥0吗(根据相关系数的计算公式)

NO.PZ2021061603000034

问题如下:

Consider two variables, A and B. If variable A has a mean of-0.56, variable B has a mean of 0.23, and the covariance between the two variables is positive, the correlation between these two variables is:

选项:

A. negative.

B. zero.

C. positive.

解释:

C is correct. The correlation coefficient is positive because the covariance is Dositive. The fact that one or both variables have a negative mean does not affect the sign of the correlation coefficient.

根据公式得出,标准差的概念。
1 个答案

星星_品职助教 · 2021年08月10日

同学你好,

对的。直接当成一个结论记忆就可以了。不用每次都通过公式推导了。

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