condition mean min max ZT0-3 3.2174500000000004 3.2174500000000004 3.2174500000000004 ZT4-7 4.02417 4.02417 4.02417 ZT8-11 2.358955 2.358955 2.358955 ZT12-15 2.236475 2.236475 2.236475 ZT16-19 4.638885 4.638885 4.638885 ZT20-23 2.48114 2.48114 2.48114