condition mean min max ZT0-3 11.85 11.85 11.85 ZT4-7 18.8 18.8 18.8 ZT8-11 9.3 9.3 9.3 ZT12-15 19.5 19.5 19.5 ZT16-19 3.05 3.05 3.05 ZT20-23 31.05 31.05 31.05