condition mean min max ZT0-3 21.8 21.8 21.8 ZT4-7 20.6 20.6 20.6 ZT8-11 11.2 11.2 11.2 ZT12-15 15.9 15.9 15.9 ZT16-19 18.3 18.3 18.3 ZT20-23 6.05 6.05 6.05