condition mean min max ZT0-3 4.5 4.5 4.5 ZT4-7 28.9 28.9 28.9 ZT8-11 8.4 8.4 8.4 ZT12-15 18.8 18.8 18.8 ZT16-19 17.85 17.85 17.85 ZT20-23 8.05 8.05 8.05