condition mean min max ZT0-3 3.2 3.2 3.2 ZT4-7 7.6 7.6 7.6 ZT8-11 11.2 11.2 11.2 ZT12-15 9.7 9.7 9.7 ZT16-19 24.049999999999997 24.049999999999997 24.049999999999997 ZT20-23 11.45 11.45 11.45