二重积分可以用来得到关于这个区域的某些信息，或者这个区域上的一个函数的平均值，等等。

We can use that to get information about maybe the region or about the average value of a function in that region and so on.

youdao

平均值、合计和其他类型的汇总数据无法通过仅仅使用一个映射函数来实现。

Averages, summations, and other summary types of data are not possible with just a map function.

youdao

然后我可以使用内置的聚合函数来获取过期天数的大小和总和并计算平均值。

I can then use built-in aggregate functions on the array to get the size and sum of those days overdue and compute an average.

youdao

And then I could also do a Gaussian one here, with the mean of and the standard deviation of volatility divided by 2.

然后我在这里再写一个高斯分布的函数，它的浮动值的平均值和,标准偏差值都除了2。

麻省理工公开课 - 计算机科学及编程导论课程节选