condition mean min max ZT0-3 8.649999999999999 8.649999999999999 8.649999999999999 ZT4-7 11.3 11.3 11.3 ZT8-11 10.85 10.85 10.85 ZT12-15 24.299999999999997 24.299999999999997 24.299999999999997 ZT16-19 34.7 34.7 34.7 ZT20-23 23.400000000000002 23.400000000000002 23.400000000000002