为什么不是-4.1589？

问题如下：

3. Based on Exhibits 1 and 2, the correlation between the debt ratio and the short interest ratio is closest to:

选项：

−0.3054.

0.0933.

0.3054.

解释：

A is correct.

The correlation coefficient equals the covariance between

variables X and Y divided by the product of the standard deviations of

variables X and Y, as follows:

$\frac{\frac{-9.2430}{49}}{\sqrt{\frac{2.2225}{49}\times\sqrt{\frac{412.2042}{49}}}}=\frac{-0.1886327}{0.2130\times2.9004}=-0.3054$