condition mean min max ZT0-3 20.8 20.8 20.8 ZT4-7 3.4 3.4 3.4 ZT8-11 8.35 8.35 8.35 ZT12-15 3.5 3.5 3.5 ZT16-19 4.1 4.1 4.1 ZT20-23 7.4 7.4 7.4