Smokers   Income  Age
    38         1      1
    42         1      2
    14         1      3
    41         2      1
    41         2      2
    16         2      3
    36         3      1
    39         3      2
    18         3      3
    32         4      1
    36         4      2
    15         4      3
    28         5      1
    33         5      2
    17         5      3