condition mean min max ZT0-3 47.5 47.5 47.5 ZT4-7 20.8 20.8 20.8 ZT8-11 22.6 22.6 22.6 ZT12-15 31.0 31.0 31.0 ZT16-19 37.75 37.75 37.75 ZT20-23 11.95 11.95 11.95