You take all the risky assets ... and you analyze them first to get their-- you have to do a statistical analysis to get their expected returns, their variances, and their covariances.

你需要对所有的风险资产进行分析,首先要得到它们的-,你必须要做一个统计分析,算出它们的预期收益率，方差，和它们的协方差。

They might say my sample period was off, ... but that's what the theory-- ... using my data for the sample period that I computed-- the expected returns and co-variances says one should do.

他们可能说我的采样周期是有问题的，不过我的结果都是靠理论-,我采用自己收集的数据计算出-,预期收益和协方差可以用来指导我们的投资行为。

But, I've dropped that assumption and now I'm going on to assuming that they're taking account of their dependence on each other, taking account of their different expected returns, and taking account of their different covariances and variances; so that's what we've got.

不过我已经放弃了那个假定,我现在假定,我们需要考虑它们彼此间的相关性，它们有着不同期望收益，不同的协方差和方差;,这是我们所学到的。