condition mean min max ZT0-3 7.300000000000001 7.300000000000001 7.300000000000001 ZT4-7 19.9 19.9 19.9 ZT8-11 19.299999999999997 19.299999999999997 19.299999999999997 ZT12-15 6.75 6.75 6.75 ZT16-19 3.15 3.15 3.15 ZT20-23 7.1 7.1 7.1