condition mean min max ZT0-3 20.5 20.5 20.5 ZT4-7 27.5 27.5 27.5 ZT8-11 12.6 12.6 12.6 ZT12-15 21.15 21.15 21.15 ZT16-19 19.25 19.25 19.25 ZT20-23 17.95 17.95 17.95