condition mean min max ZT0-3 5.55 5.55 5.55 ZT4-7 3.6 3.6 3.6 ZT8-11 17.75 17.75 17.75 ZT12-15 6.5 6.5 6.5 ZT16-19 19.35 19.35 19.35 ZT20-23 32.55 32.55 32.55