The 2 sigma comes from two standard deviation, sigma, the symbol for standard deviation.

2 sigma 来自两个均方，sigma 是均方的符号。

Readers have to wait until page 65 before reaching the first serious concept, standard deviation, which feels too late.

读者得等上65页才能接触到第一个严肃的统计学概念——，让感觉进度太慢。

The critical variable was the standard deviation of the means divided by the mean of the standard deviations.

关键变量是均值的除以的均值。

Let's say 2.79 is the standard deviation.

假设2.79是偏。

Do you know how to calculate the standard deviation ?

你知道如何计算吗？

What if we got two standard deviations more conscientious?

如果我们得到两个更认真的呢？

So why even talk about the standard deviation?

那么为什么还要谈论呢？

The calculated standard deviation of the data in Table 2 is 12.14 .

表2中数据的计算为12.14。

Raymond, you were the one who scored one standard deviation higher than Debra.

雷蒙德，你的成绩应该比黛布拉高一个等级。

Table 4 compares the percentages based on using the standard deviation and the variances.

表 4 比较了基于和方的百分比。

So, you know M for mean,   as for standard deviation but both in Greek.

所以，你知道 M 代表平均值，M 代表，但两者都是希腊语。

So based on the data given for this population, and using the standard deviation formula, what do you think this variable is?

以这个口数据为基础再用公式，你觉得变量是多少？

The standard deviation is just the square root of the variance.

就是方的平方根。

So this whole term right here is how many standard deviations we are away from the mean.

因此，这里的整个项表示我们距离均值有多少个。

Which basically just rescales the units so that the standard  deviation of our expression will equal one.

这基本上只是重新调整单位，使我们的表达式的等于 1。

And we'll talk-- and we'll move into the standard deviation.

我们将讨论——我们将进入。

But the sigma right here, that is just the standard deviation of the distribution.

但这里的西格玛，其实就是分布的。

DUCKWORTH: So, we've not only gotten smarter, we've become two standard deviations smarter than we were 100 years ago.

DUCKWORTH：所以，我们不仅变得更聪明了，而且比 100 年前更聪明了两个。

Standard deviation squared is just the variance, right?

平方就是方，对吧？

The total variation is based on the standard deviation.

总变异基于。