condition mean min max ZT0-3 11.9 11.9 11.9 ZT4-7 23.8 23.8 23.8 ZT8-11 15.9 15.9 15.9 ZT12-15 16.9 16.9 16.9 ZT16-19 20.55 20.55 20.55 ZT20-23 10.7 10.7 10.7