7% 77% is class average and the standard deviation was 17% so you can see where things lie. 50% is a pass.

7是平均水平，标准偏差是%,这就是事情所在，50%就及格。

麻省理工公开课 - 固态化学导论课程节选

I computed the returns on the stocks, bonds, and oil for every year from 1983 and I computed the average returns, which I take as the expected returns, I took the standard deviations, and I took the covariance.

我计算了从1983年以来每年的股票,债券和石油的收益，从而得出平均收益率，这些平均收益率作为预期收益率，然后算得标准差及协方差。

耶鲁公开课 - 金融市场课程节选