condition mean min max ZT0-3 2.217811666666667 1.55087 3.0991400000000002 ZT4-7 1.70275 1.70275 1.70275 ZT8-11 1.6862249999999999 1.6862249999999999 1.6862249999999999 ZT12-15 2.7186025000000003 2.047095 3.39011 ZT16-19 2.731045 2.731045 2.731045 ZT20-23 1.8020100000000001 1.8020100000000001 1.8020100000000001