condition mean min max ZT0-3 6.45 6.45 6.45 ZT4-7 6.8 6.8 6.8 ZT8-11 24.3 24.3 24.3 ZT12-15 15.15 15.15 15.15 ZT16-19 15.45 15.45 15.45 ZT20-23 23.5 23.5 23.5