condition mean min max ZT0-3 21.7 21.7 21.7 ZT4-7 8.0 8.0 8.0 ZT8-11 19.9 19.9 19.9 ZT12-15 9.2 9.2 9.2 ZT16-19 44.35 44.35 44.35 ZT20-23 10.8 10.8 10.8