condition mean min max ZT0-3 3.8 3.8 3.8 ZT4-7 2.5 2.5 2.5 ZT8-11 16.1 16.1 16.1 ZT12-15 2.6999999999999997 2.6999999999999997 2.6999999999999997 ZT16-19 14.4 14.4 14.4 ZT20-23 11.8 11.8 11.8