condition mean min max ZT0-3 8.2 8.2 8.2 ZT4-7 6.5 6.5 6.5 ZT8-11 31.35 31.35 31.35 ZT12-15 4.3 4.3 4.3 ZT16-19 8.25 8.25 8.25 ZT20-23 9.15 9.15 9.15