import pandas as pd
from pandas import Series,DataFrame
import numpy as np

a=[98,83,65,72,79,76,75,94,91,77,63,83,89,69,64,78,63,86,91,72,71,72,70,80,65,70,62,74,71,76]
np.mean(a),np.mean(np.sort(a)[1:5]),np.sort(a)

求众数的函数

def get_mode(arr):
    mode=[]
    arr_appear=dict((a,arr.count(a))for a in arr) # 统计各个元素出现的次数
    if max(arr_appear.values())==1:
        return "no mode"
    else:
        for k,v in arr_appear.items(): # 否则，出现次数最大的数字，就是众数 
            if v ==max(arr_appear.values()):
                mode.append(k)
    return mode

get_mode(a)

np.var(a),np.std(a)

a=Series(a)

a.skew() #偏态系数

a.kurt()#峰度系数

a.describe()
假设检验

df=DataFrame({'data1' : np.random.randn(5),
                'data2' : np.random.randn(5)})
df.cov(),df.corr()

from scipy import stats as ss
df=DataFrame({'data':[10.1,10,9.8,10.5,9.7,10.1,9.9,10.2,10.3,9.9]})
ss.ttest_1samp(a=df,popmean=10)