condition mean min max ZT0-3 9.4 9.4 9.4 ZT4-7 1.8 1.8 1.8 ZT8-11 4.1 4.1 4.1 ZT12-15 7.55 7.55 7.55 ZT16-19 23.7 23.7 23.7 ZT20-23 9.7 9.7 9.7