condition mean min max ZT0-3 8.15 8.15 8.15 ZT4-7 3.3 3.3 3.3 ZT8-11 6.5 6.5 6.5 ZT12-15 4.85 4.85 4.85 ZT16-19 5.9 5.9 5.9 ZT20-23 18.65 18.65 18.65