condition mean min max ZT0-3 1.7 1.7 1.7 ZT4-7 8.1 8.1 8.1 ZT8-11 7.1 7.1 7.1 ZT12-15 20.6 20.6 20.6 ZT16-19 33.45 33.45 33.45 ZT20-23 7.8 7.8 7.8