condition mean min max ZT0-3 7.5 7.5 7.5 ZT4-7 7.7 7.7 7.7 ZT8-11 5.05 5.05 5.05 ZT12-15 12.299999999999999 12.299999999999999 12.299999999999999 ZT16-19 4.4 4.4 4.4 ZT20-23 16.0 16.0 16.0