condition mean min max ZT0-3 13.65 13.65 13.65 ZT4-7 17.8 17.8 17.8 ZT8-11 17.75 17.75 17.75 ZT12-15 20.35 20.35 20.35 ZT16-19 25.5 25.5 25.5 ZT20-23 8.3 8.3 8.3