python筆記：6.1.1.3抽樣分佈_求均值、方差

 

# -*- coding: utf-8 -*-
"""
Created on Tue Jun 11 08:44:18 2019

@author: User
"""

'''
設一個總體，含有4個個體，即總容量爲N=4，；4個個體分別爲2、4、6、8。
求總體均值、方差
'''
import numpy as np
import pandas as pd

pop=np.array([2,4,6,8]) #pop爲總體數據

print("\n 計算總體方差 pop.var(ddof=0)")
print(pop.var(ddof=0)) 
#print(pop.std()) 

print("\n 計算總體均值 pop.mean")
print(pop.mean())

print("===============================")

print("\n 以下是所有樣本的均值數據")
miu=np.array([2,3,4,5,3,4,5,6,4,5,6,7,5,6,7,8])

print("\n 計算樣本方差 miu.var(ddof=0)")
print(miu.var(ddof=0))  

print("\n 計算樣本均值 miu.mean")
print(miu.mean())

運行：

 計算總體方差 pop.var(ddof=0)
5.0

 計算總體均值 pop.mean
5.0
===============================

 以下是所有樣本的均值數據

 計算樣本方差 miu.var(ddof=0)
2.5

 計算樣本均值 miu.mean
5.0