condition mean min max ZT0-3 23.1 23.1 23.1 ZT4-7 5.8 5.8 5.8 ZT8-11 3.5 3.5 3.5 ZT12-15 13.5 13.5 13.5 ZT16-19 19.15 19.15 19.15 ZT20-23 4.05 4.05 4.05