condition mean min max ZT0-3 2.968045 2.968045 2.968045 ZT4-7 2.6327350000000003 2.6327350000000003 2.6327350000000003 ZT8-11 2.115005 2.115005 2.115005 ZT12-15 2.109525 2.109525 2.109525 ZT16-19 4.07375 4.07375 4.07375 ZT20-23 3.497725 3.497725 3.497725