In [5]:

    

# Import modules
import pandas as pd


    

In [6]:

    

# Example dataframe
raw_data = {'regiment': ['Nighthawks', 'Nighthawks', 'Nighthawks', 'Nighthawks', 'Dragoons', 'Dragoons', 'Dragoons', 'Dragoons', 'Scouts', 'Scouts', 'Scouts', 'Scouts'], 
        'company': ['1st', '1st', '2nd', '2nd', '1st', '1st', '2nd', '2nd','1st', '1st', '2nd', '2nd'], 
        'name': ['Miller', 'Jacobson', 'Ali', 'Milner', 'Cooze', 'Jacon', 'Ryaner', 'Sone', 'Sloan', 'Piger', 'Riani', 'Ali'], 
        'preTestScore': [4, 24, 31, 2, 3, 4, 24, 31, 2, 3, 2, 3],
        'postTestScore': [25, 94, 57, 62, 70, 25, 94, 57, 62, 70, 62, 70]}
df = pd.DataFrame(raw_data, columns = ['regiment', 'company', 'name', 'preTestScore', 'postTestScore'])
df


    

    
Out[6]:






  

    

      

      
regiment
      
company
      
name
      
preTestScore
      
postTestScore
    
  
  

    

      
0
      
Nighthawks
      
1st
      
Miller
      
4
      
25
    
    

      
1
      
Nighthawks
      
1st
      
Jacobson
      
24
      
94
    
    

      
2
      
Nighthawks
      
2nd
      
Ali
      
31
      
57
    
    

      
3
      
Nighthawks
      
2nd
      
Milner
      
2
      
62
    
    

      
4
      
Dragoons
      
1st
      
Cooze
      
3
      
70
    
    

      
5
      
Dragoons
      
1st
      
Jacon
      
4
      
25
    
    

      
6
      
Dragoons
      
2nd
      
Ryaner
      
24
      
94
    
    

      
7
      
Dragoons
      
2nd
      
Sone
      
31
      
57
    
    

      
8
      
Scouts
      
1st
      
Sloan
      
2
      
62
    
    

      
9
      
Scouts
      
1st
      
Piger
      
3
      
70
    
    

      
10
      
Scouts
      
2nd
      
Riani
      
2
      
62
    
    

      
11
      
Scouts
      
2nd
      
Ali
      
3
      
70
    
  

In [7]:

    

# Create a grouping object. In other words, create an object that
# represents that particular grouping. In this case we group
# pre-test scores by the regiment.
regiment_preScore = df['preTestScore'].groupby(df['regiment'])


    

In [8]:

    

# Display the mean value of the each regiment's pre-test score
regiment_preScore.mean()


    

    
Out[8]:





regiment
Dragoons      15.50
Nighthawks    15.25
Scouts         2.50
Name: preTestScore, dtype: float64