condition mean min max ZT0-3 20.5 20.5 20.5 ZT4-7 4.4 4.4 4.4 ZT8-11 4.7 4.7 4.7 ZT12-15 7.35 7.35 7.35 ZT16-19 12.65 12.65 12.65 ZT20-23 13.0 13.0 13.0