NO.PZ2020011101000032
问题如下:
Variances are usually transformed into volatilities by taking the square root. This changes the units from squared returns to returns. Why isn’t the same transformation used on covariances?
解释:
Covariance may have either sign, and so the square root transformation is not reliable if the sign is negative. Transformation to or correlation is preferred when examining the magnitude of a covariance.
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