condition mean min max ZT0-3 5.25 5.25 5.25 ZT4-7 1.8 1.8 1.8 ZT8-11 8.75 8.75 8.75 ZT12-15 2.6500000000000004 2.6500000000000004 2.6500000000000004 ZT16-19 6.75 6.75 6.75 ZT20-23 16.8 16.8 16.8