Statistics 简明教程

Statistics - Standard Deviation

标准差是所有项目离平均值的平方差的平均值的平方根。在符号中用 ${\sigma}$ 表示。

Standard deviation is the square root of the average of squared deviations of the items from their mean. Symbolically it is represented by ${\sigma}$.

我们准备讨论为以下三种类型序列计算 Standard deviation 的方法:

We’re going to discuss methods to compute the Standard deviation for three types of series:

Individual Data Series

当数据是以个体为基础给出时。以下是关于个体序列的一个例子:

When data is given on individual basis. Following is an example of individual series:

Items

5

10

20

30

40

50

60

70

Discrete Data Series

当数据与其频率一起给出时。以下是离散序列的一个例子:

When data is given alongwith their frequencies. Following is an example of discrete series:

Items

5

10

20

30

40

50

60

70

Frequency

2

5

1

3

12

0

5

7

Continuous Data Series

当数据根据范围及其频率给出时。以下是连续序列的一个例子:

When data is given based on ranges alongwith their frequencies. Following is an example of continous series:

Items

0-5

5-10

10-20

20-30

30-40

Frequency

2

5

1

3

12