condition mean min max ZT0-3 3.55 3.55 3.55 ZT4-7 11.7 11.7 11.7 ZT8-11 34.95 34.95 34.95 ZT12-15 15.350000000000001 15.350000000000001 15.350000000000001 ZT16-19 12.9 12.9 12.9 ZT20-23 16.5 16.5 16.5