When you get--this is Rituparna, counting the leaves on a tree-- you can estimate, from a sample, the population expected values.

如果你...像数叶子的睿都巴若那一样,只有部分样本的话,你可以来估计总体均值

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We can define it in a couple of different ways depending on whether we're talking about sample mean or population mean.

我们有几种不同的方式去定义这个概念,取决于我们指的是,样本均值还是总体均值

耶鲁公开课 - 金融市场课程节选

It's the truth, but there are also sample means.

这些是真实的值,但同时也有样本均值

耶鲁公开课 - 金融市场课程节选