I feel like I have to introduce concepts like variance and co-variance and correlation in order to talk about finance; so that's what we'll do in Lecture Two.

我会讲到像方差,协方差,相关系数,这样的概念,为金融学的内容作一些铺垫,我们会在第二课讲到

耶鲁公开课 - 金融市场课程节选

Another concept that's very basic here is covariance.

另一个基本的概念是协方差

耶鲁公开课 - 金融市场课程节选