So, that is not--your return is actually higher than 2.51% on an annualized basis.

所以,你的实际年收益率,应该高于2.51%

耶鲁公开课 - 金融市场课程节选

Now, underlying our theory is the idea that we measure the outcome of your investment in your portfolio by the mean of the return on the portfolio and the variance of the return on the portfolio.

而理论的基础是,我们通过计算,组合收益率的均值，和组合收益率的方差,来衡量一个投资组合的优劣。

耶鲁公开课 - 金融市场课程节选