condition mean min max ZT0-3 5.050000000000001 5.050000000000001 5.050000000000001 ZT4-7 3.1 3.1 3.1 ZT8-11 9.75 9.75 9.75 ZT12-15 1.9000000000000001 1.9000000000000001 1.9000000000000001 ZT16-19 14.15 14.15 14.15 ZT20-23 9.1 9.1 9.1