n. 协方差

[化] 协方差

[ noun ]
(statistics) the mean value of the product of the deviations of two variates from their respective means
<noun.cognition>

covariance \covariance\ n.
a statistical measure of the relationship of two variables,
formed by multiplying the difference of each variable from
its mean, both variables being measured at the same time, and
averaging all such products.
[WordNet 1.5 +PJC]