condition mean min max ZT0-3 13.65 13.65 13.65 ZT4-7 6.3 6.3 6.3 ZT8-11 18.85 18.85 18.85 ZT12-15 5.35 5.35 5.35 ZT16-19 12.95 12.95 12.95 ZT20-23 6.4 6.4 6.4