# special IPython command to prepare the notebook for matplotlib
%matplotlib inline 

import numpy as np
import pandas as pd
import matplotlib.pyplot as plt

#your code here

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"""
Function
--------
mergeByYear

Return a merged DataFrame containing the income, 
country name and region for a given year. 

Parameters
----------
year : int
    The year of interest

Returns
-------
a DataFrame
   A pandas DataFrame with three columns titled 
   'Country', 'Region', and 'Income'. 

Example
-------
>>> mergeByYear(2010)
"""
#your code here

#your code here

"""
Function
--------
ratioNormals

Return ratio of these two proportions: 
    Pr(X > a)/Pr(Y > a) as function of 
    the difference in the average of X 
    and the average of Y. 

Parameters
----------
diff : difference in the average of X 
    and the average of Y. 
a : cutoff value

Returns
-------
Returns ratio of these two proportions: 
    Pr(X > a)/Pr(Y > a)
    
Example
-------
>>> ratioNormals(diff = 1, a = 2)
"""
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