condition mean min max ZT0-3 17.5 17.5 17.5 ZT4-7 6.6 6.6 6.6 ZT8-11 38.05 38.05 38.05 ZT12-15 8.65 8.65 8.65 ZT16-19 14.6 14.6 14.6 ZT20-23 2.25 2.25 2.25