condition mean min max ZT0-3 8.164056666666667 1.38097 12.4362 ZT4-7 0.8236334999999999 0.8236334999999999 0.8236334999999999 ZT8-11 1.45092 1.45092 1.45092 ZT12-15 4.2404225 3.03571 5.4451350000000005 ZT16-19 7.1256900000000005 7.1256900000000005 7.1256900000000005 ZT20-23 13.00815 13.00815 13.00815