condition mean min max ZT0-3 24.9 24.9 24.9 ZT4-7 3.3 3.3 3.3 ZT8-11 2.55 2.55 2.55 ZT12-15 5.15 5.15 5.15 ZT16-19 9.15 9.15 9.15 ZT20-23 16.55 16.55 16.55