condition mean min max ZT0-3 21.25 21.25 21.25 ZT4-7 3.3 3.3 3.3 ZT8-11 1.6 1.6 1.6 ZT12-15 8.299999999999999 8.299999999999999 8.299999999999999 ZT16-19 9.5 9.5 9.5 ZT20-23 10.799999999999999 10.799999999999999 10.799999999999999