condition mean min max ZT0-3 9.4 9.4 9.4 ZT4-7 3.2 3.2 3.2 ZT8-11 17.9 17.9 17.9 ZT12-15 15.4 15.4 15.4 ZT16-19 23.299999999999997 23.299999999999997 23.299999999999997 ZT20-23 13.0 13.0 13.0