condition mean min max ZT0-3 3.25 3.25 3.25 ZT4-7 3.3 3.3 3.3 ZT8-11 14.75 14.75 14.75 ZT12-15 5.6 5.6 5.6 ZT16-19 4.25 4.25 4.25 ZT20-23 1.4 1.4 1.4