Table 4.1
    Obs       Income    Educ  
     1         20.5      12
     2         31.5      16 
     3         47.7      18          
     4         26.2      16          
     5         44.0      12          
     6         8.28      12          
     7         30.8      16          
     8         17.2      12          
     9         19.9      10          
    10         9.96      12          
    11         55.8      16  
    12         25.2      20  
    13         29.0      12  
    14         85.5      16   
    15         15.1      10   
    16         28.5      18
    17         21.4      16
    18         17.7      20
    19         6.42      12
    20         84.9      16