condition mean min max ZT0-3 6.15 6.15 6.15 ZT4-7 4.5 4.5 4.5 ZT8-11 12.9 12.9 12.9 ZT12-15 10.95 10.95 10.95 ZT16-19 13.75 13.75 13.75 ZT20-23 28.85 28.85 28.85