condition mean min max ZT0-3 21.5 21.5 21.5 ZT4-7 16.5 16.5 16.5 ZT8-11 9.35 9.35 9.35 ZT12-15 2.7 2.7 2.7 ZT16-19 5.15 5.15 5.15 ZT20-23 1.9 1.9 1.9