condition mean min max ZT0-3 2.0619262492500003 0.362682104 3.7611703945000006 ZT4-7 7.2539210585 6.4918753065 8.0159668105 ZT8-11 7.866376492500001 7.672517425500001 8.0602355595 ZT12-15 6.51746024675 6.044091830499999 6.990828663 ZT16-19 4.779455528250001 4.4019816415 5.1569294150000005 ZT20-23 5.429149618 4.8826153535 5.9756838825