Do I go out to Harvard yard and take a random sample ? of sophomores to study meditation?

是不是可以在哈佛大二学生里随机抽样,来研究冥想？

哈佛公开课 - 幸福课课程节选

And I say if you took a random sample of the Americans: "When you woke up in the middle of the night" and said: "What does the America stand for?"

我觉得如果给美国人做个抽样调查：,半夜醒来的时候“,被问到，美国人主张什么“

普林斯顿公开课 - 国际座谈会课程节选

And the other thing you can do is take self reports like the ones you're doing, hopefully do enough of them, and a random enough sample of the population, that you can extrapolate from that sample to the whole population, and try to estimate what people are eating in that way.

还有其他可以做的,比如大家正在做的这种个体调查,希望能把它做的充分些,如果有充足的随机样本,就可以从样本推断出,整个总体,从而推断哪类人有这样的饮食习惯

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

Covariance is--we'll call it--now we have two random variables, so cov... I'll just talk about it in a sample term.

协方差是...我们有两个随机变量,x和y的协方差是,从样本的角度来说

耶鲁公开课 - 金融市场课程节选