condition mean min max ZT0-3 5.05 5.05 5.05 ZT4-7 4.7 4.7 4.7 ZT8-11 11.9 11.9 11.9 ZT12-15 11.8 11.8 11.8 ZT16-19 21.95 21.95 21.95 ZT20-23 31.5 31.5 31.5