condition mean min max ZT0-3 18.25 18.25 18.25 ZT4-7 2.3 2.3 2.3 ZT8-11 19.3 19.3 19.3 ZT12-15 6.95 6.95 6.95 ZT16-19 31.4 31.4 31.4 ZT20-23 4.7 4.7 4.7