condition mean min max ZT0-3 4.05 4.05 4.05 ZT4-7 1.9 1.9 1.9 ZT8-11 2.75 2.75 2.75 ZT12-15 2.9000000000000004 2.9000000000000004 2.9000000000000004 ZT16-19 12.6 12.6 12.6 ZT20-23 4.65 4.65 4.65