condition mean min max ZT0-3 4.449999999999999 4.449999999999999 4.449999999999999 ZT4-7 1.9 1.9 1.9 ZT8-11 25.5 25.5 25.5 ZT12-15 8.7 8.7 8.7 ZT16-19 3.9000000000000004 3.9000000000000004 3.9000000000000004 ZT20-23 6.35 6.35 6.35