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

You've got a sample of it on your handout.

你们手上的讲稿里有一份这首诗。

耶鲁公开课 - 现代诗歌课程节选

One is in the U.S.at the Centers for Disease Control, where there is a sample of variola, which is kept, you know, frozen on ice in a heavily guarded facility.

一个在美国的疾病控制中心,那有一支天花病毒的样本,冰冻后置于重重保护之下

耶鲁公开课 - 生物医学工程探索课程节选