The standard deviation is the square root of the variance.

标准差是方差的平方根

耶鲁公开课 - 金融市场课程节选

Depending on where the assets expected returns are and the assets' standard deviations, we can see that we might be able to do better than--have a lower variance than either asset.

根据资产的预期收益,以及收益的标准差，可以看到我们有更好的选择,这里的方差值比以上两种方案都要低。

耶鲁公开课 - 金融市场课程节选

What we want to do now is compute the mean and variance of the portfolio-- or the mean and standard deviation, since standard deviation is the square root of the variance-- for different combinations of the portfolios.

我们现在要做的是,计算这个投资组合的均值和方差-,或者均值和标准差，因为标准差的平方就等于方差-,这对任何投资组合都是一样的。

耶鲁公开课 - 金融市场课程节选

Or, especially when talking about estimates of the variance, we sometimes say S2 or we say standard deviation2.

又或者,在讨论方差估计的时候,我们常用S2,称为标准差的平方

耶鲁公开课 - 金融市场课程节选