condition mean min max ZT0-3 12.7 12.7 12.7 ZT4-7 20.7 20.7 20.7 ZT8-11 5.5 5.5 5.5 ZT12-15 9.85 9.85 9.85 ZT16-19 9.35 9.35 9.35 ZT20-23 31.6 31.6 31.6