What is the 95% confidence interval for the population mean?

什么是95%的人口置信区间是什么意思？

youdao

The population mean is often written "x-bar." If you have a sample with n observations, it's the summation i = 1 to n of xi/n--that's the average.

人口均值经常写成“x-条形柱”，如果你有一个样本有n个观测者，是从 i=1到n和的xi/n，这是平均值。

youdao

I mean, as the population grows and there are more vehicles on the roads and there's more machinery, surely they can't depend so much on sugar cane?

我是说，随着人口增长，路上车辆更多了，机械也更多了，他们肯定不能只依赖于甘蔗（作为生物燃料）吧？

youdao

The population mean is often written "X-bar."

总体均值一般写作X拔

耶鲁公开课 - 金融市场课程节选

Well, a cross-sectional study would mean that you'd get a random group of the population and measure them in 1970 and then take another random group five years later and measure them, but it wouldn't be the same people necessarily, it would be different groups of people.

那么,横断面研究就是,1970年你在人群中随意选择一组人,并记录下相关数据,然后,五年后再随意选择一组人记录数据,但这不需要是同一组人,通常是不同的人

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

But there is also economic sense to it, as opening these top positions up to the other half of the population will mean an even more talented slate of candidates to choose from, making sure the best and brightest are better and brighter.

FORBES: Lean In, Trickle Down: The False Promise of Sheryl Sandberg's Theory of Change

The population does mean you get a more precise estimate of BMI simply by averaging over large numbers.

BBC: BMI: Does the Body Mass Index need fixing?

Putting a lid on the prison population will mean restraining sentences.

ECONOMIST: Prison expansion