>import statistics
> statistics.mean([1,2,3,4,5,6,7,8,9])#使用整数列表做参数
5
> statistics.mean(range(1,10))#使用range对象做参数
5
>import fractions
> x =[(3,7),(1,21),(5,3),(1,3)]
> y =[fractions.Fraction(*item)for item in x]
> y
[Fraction(3,7),Fraction(1,21),Fraction(5,3),Fraction(1,3)]
> statistics.mean(y)#使用包含分数的列表做参数
Fraction(13,21)
>import decimal
> x =('0.5','0.75','0.625','0.375')
> y = map(decimal.Decimal, x)
> statistics.mean(y)
Decimal('0.5625')

> statistics.median([1,3,5,7])#偶数个样本时取中间两个数的平均数
4.0
> statistics.median_low([1,3,5,7])#偶数个样本时取中间两个数的较小者
3
> statistics.median_high([1,3,5,7])#偶数个样本时取中间两个数的较大者
5
> statistics.median(range(1,10))
5
> statistics.median_low([5,3,7]), statistics.median_high([5,3,7])
(5,5)
> statistics.median_grouped([5,3,7])
5.0
> statistics.median_grouped([52,52,53,54])
52.5
> statistics.median_grouped([1,3,3,5,7])
3.25
> statistics.median_grouped([1,2,2,3,4,4,4,4,4,5])
3.7
> statistics.median_grouped([1,2,2,3,4,4,4,4,4,5], interval=2)
3.4

> statistics.mode([1,3,5,7])#无法确定出现次数最多的唯一元素
Traceback(most recent call last):
File"<pyshell#27>", line 1,in<module>
statistics.mode([1,3,5,7])#无法确定出现次数最多的唯一元素
File"D:\Python36\lib\statistics.py", line 507,in mode
'no unique mode; found %d equally common values'% len(table)
statistics.StatisticsError: no unique mode; found 4 equally common values
> statistics.mode([1,3,5,7,3])
3
> statistics.mode(["red","blue","blue","red","green","red","red"])
'red'

> statistics.pstdev([1.5,2.5,2.5,2.75,3.25,4.75])
0.986893273527251
> statistics.pstdev(range(20))
5.766281297335398

> statistics.pvariance([1.5,2.5,2.5,2.75,3.25,4.75])
0.9739583333333334
> x =[1,2,3,4,5,10,9,8,7,6]
> mu = statistics.mean(x)
> mu
5.5
> statistics.pvariance([1,2,3,4,5,10,9,8,7,6], mu)
8.25
> statistics.pvariance(range(20))
33.25
> statistics.pvariance((random.randint(1,10000)for i in range(30)))
>import random
> statistics.pvariance((random.randint(1,10000)for i in range(30)))
7117280.4