condition mean min max ZT0-3 6.367505 4.205579999999999 8.359265 ZT4-7 2.5030259999999998 2.5030259999999998 2.5030259999999998 ZT8-11 2.4094315 2.4094315 2.4094315 ZT12-15 4.0204775 3.824395 4.216559999999999 ZT16-19 2.7118149999999996 2.7118149999999996 2.7118149999999996 ZT20-23 6.684735 6.684735 6.684735