整群抽样

Python 抽样

James Chapman

Curriculum Manager, DataCamp

分层抽样 vs. 整群抽样

分层抽样

将总体划分为子组
对每个子组做简单随机抽样

整群抽样

先用简单随机抽样选取部分子组
仅对选中的子组做简单随机抽样

咖啡品种

按行列排列的咖啡豆。

varieties_pop = list(coffee_ratings['variety'].unique())

[None, 'Other', 'Bourbon', 'Catimor', 
'Ethiopian Yirgacheffe','Caturra', 
'SL14', 'Sumatra', 'SL34', 'Hawaiian Kona',
'Yellow Bourbon', 'SL28', 'Gesha', 'Catuai',
'Pacamara', 'Typica', 'Sumatra Lintong',
'Mundo Novo', 'Java', 'Peaberry', 'Pacas',
'Mandheling', 'Ruiru 11', 'Arusha',
'Ethiopian Heirlooms', 'Moka Peaberry',
'Sulawesi', 'Blue Mountain', 'Marigojipe', 
'Pache Comun']

阶段 1：抽取子组

按行列排列的咖啡豆，除三个外其余均灰显。

import random
varieties_samp = random.sample(varieties_pop, k=3)

['Hawaiian Kona', 'Bourbon', 'SL28']

阶段 2：在各组内抽样

variety_condition = coffee_ratings['variety'].isin(varieties_samp)
coffee_ratings_cluster = coffee_ratings[variety_condition]

coffee_ratings_cluster['variety'] = coffee_ratings_cluster['variety'].cat.remove_unused_categories()

coffee_ratings_cluster.groupby("variety")\
    .sample(n=5, random_state=2021)

第 2 阶段输出

                    total_cup_points        variety       country_of_origin  ...
variety                                                                       
Bourbon       575              82.83        Bourbon               Guatemala   
              560              82.83        Bourbon               Guatemala   
              524              83.00        Bourbon               Guatemala   
              1140             79.83        Bourbon               Guatemala   
              318              83.67        Bourbon                  Brazil   
Hawaiian Kona 1291             73.67  Hawaiian Kona  United States (Hawaii)   
              1266             76.25  Hawaiian Kona  United States (Hawaii)   
              488              83.08  Hawaiian Kona  United States (Hawaii)   
              461              83.17  Hawaiian Kona  United States (Hawaii)   
              117              84.83  Hawaiian Kona  United States (Hawaii)   
SL28          137              84.67           SL28                   Kenya   
              452              83.17           SL28                   Kenya   
              224              84.17           SL28                   Kenya   
              66               85.50           SL28                   Kenya   
              559              82.83           SL28                   Kenya

多阶段抽样

整群抽样是一种多阶段抽样
可有 > 2 个阶段
例如，全国性调查可先抽州，再抽县、市、社区

Passons à la pratique !

Python 抽样