Expected value is good and variance is bad because that's risk; that's uncertainty.

期望值越高越好,方差就相反,因为方差代表着风险,也就是不确定性

耶鲁公开课 - 金融市场课程节选

I have stocks, bonds, and oil but I want also to add one more final asset, we'll call it the riskless asset, long-term bonds are somewhat uncertain and variable because they're long-term.

有股票，债券和石油,我还想再增加最后一种资产，我们称之为无风险资产，由于长期债券持有期限很长,存在一定不确定性及风险。

耶鲁公开课 - 金融市场课程节选