condition mean min max ZT0-3 7.8 7.8 7.8 ZT4-7 9.5 9.5 9.5 ZT8-11 19.35 19.35 19.35 ZT12-15 6.0 6.0 6.0 ZT16-19 27.049999999999997 27.049999999999997 27.049999999999997 ZT20-23 5.9 5.9 5.9