On an average day, nearly everyone fifteen years of age and older took part in a non-work activity like watching television, socializing or exercising.

VOA: special.2011.07.22

One person might be a little low one day, another person might be high, a lot of people might-- you might happen to have captured them on an average day, but overall it averages out, so you get a representative sample.

一个人可能某一天少吃些,另一个人可能多吃些,很多人都会这样,你可能正好得出人们,平均每天的摄入量,但把它的整体平均一下,就得到有代表性的结果

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

It can do this between sunrise and noon on a clear day with an average outside temperature of thirty-two degrees Celsius.

VOA: special.2009.04.20

The study also says American children eat an average of three snacks a day on top of three regular meals, and the snacks account for almost one third of their daily calories.

VOA: standard.2010.03.09