Python Pandas:rolling_kurt 对比 scipy.stats.kurtosis

Python Pandas: rolling_kurt vs. scipy.stats.kurtosis

我试图找出为什么以下代码 returns 样本峰度的不同值:

import pandas
import scipy
e = pandas.DataFrame([1, 2, 3, 4, 5, 4, 3, 2, 1])
print "pandas.rolling_kurt:\n", pandas.rolling_kurt(e, window=9)
print "\nscipy.stats.kurtosis:", scipy.stats.kurtosis(e)

我得到的输出:

pandas.rolling_kurt:
          0
0       NaN
1       NaN
2       NaN
3       NaN
4       NaN
5       NaN
6       NaN
7       NaN
8 -1.060058

scipy.stats.kurtosis: [-1.15653061]

我试过 pearson vs fisher 设置,但无济于事。

设置bias=False似乎可以做到:

In [3]: scipy.stats.kurtosis(e,bias=False)
Out[3]: array([-1.06005831])