condition mean min max ZT0-3 3.25 3.25 3.25 ZT4-7 1.2 1.2 1.2 ZT8-11 1.15 1.15 1.15 ZT12-15 1.7000000000000002 1.7000000000000002 1.7000000000000002 ZT16-19 2.5 2.5 2.5 ZT20-23 8.25 8.25 8.25