condition mean min max ZT0-3 3.35 3.35 3.35 ZT4-7 2.3 2.3 2.3 ZT8-11 16.9 16.9 16.9 ZT12-15 17.0 17.0 17.0 ZT16-19 3.9 3.9 3.9 ZT20-23 9.0 9.0 9.0