来自《耶鲁大学开放课程：有关食物的心理学、生物学和政治学第12集》

where you're taking a snapshot at one point in time

你们就一个群体
of a group of individuals

开展了一次性调查
and you might, if you have enough subjects,

然后如果你们有足够多实验对象
be able to compare groups of individuals.

就可以对不同群体进行比较分析
Let's say this is a hypothetical example

举个假设性的例子
that looks at cholesterol levels, smoking and heart disease

我们就不同性别的群体调查
in a group of males and females.

他们的胆固醇水平吸烟和心脏病情况
You do this one shot in time assessment,

做个一次性评估
so let's say you get 5,000 males, 5,000 females.

假设有5000个男性和5000个女性
You do a big study on this

你们做了个大型的研究
and you get collect data where each of these X's appears.

而且收集资料填满了这些X处
What can you do with that information?

这些信息有什么用呢