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。