condition mean min max ZT0-3 3.2496466666666666 2.3557550000000003 3.7716649999999996 ZT4-7 1.84416 1.84416 1.84416 ZT8-11 3.1372799999999996 3.1372799999999996 3.1372799999999996 ZT12-15 3.0510650000000004 2.922405 3.1797250000000004 ZT16-19 3.2875199999999998 3.2875199999999998 3.2875199999999998 ZT20-23 4.636255 4.636255 4.636255