One more thing, I said they're not independent, so we have to talk about the covariance between the returns.

还有，我说过它们不是相互独立的，因此我们还需要讨论两个收益率的协方差。

耶鲁公开课 - 金融市场课程节选

That's why we need independence of the central bank; we want to have a central banker that can say no to the government.

这就是为什么我们需要独立自主的,中央银行；,我们希望有一个可以对政府说不得,中央银行家。

耶鲁公开课 - 金融市场课程节选