condition mean min max ZT0-3 19.3 19.3 19.3 ZT4-7 2.4 2.4 2.4 ZT8-11 11.3 11.3 11.3 ZT12-15 26.6 26.6 26.6 ZT16-19 37.75 37.75 37.75 ZT20-23 29.05 29.05 29.05