condition mean min max ZT0-3 6.550000000000001 6.550000000000001 6.550000000000001 ZT4-7 3.6 3.6 3.6 ZT8-11 8.1 8.1 8.1 ZT12-15 24.05 24.05 24.05 ZT16-19 9.2 9.2 9.2 ZT20-23 30.95 30.95 30.95