Association rules:
0.333  0.533  lenses=none -> prescription=hypermetrope
0.333  0.667  prescription=hypermetrope -> lenses=none
0.333  0.533  lenses=none -> astigmatic=yes
0.333  0.667  astigmatic=yes -> lenses=none
0.500  0.800  lenses=none -> tear_rate=reduced
0.500  1.000  tear_rate=reduced -> lenses=none
