condition mean min max ZT0-3 20.5 20.5 20.5 ZT4-7 12.5 12.5 12.5 ZT8-11 3.3 3.3 3.3 ZT12-15 18.349999999999998 18.349999999999998 18.349999999999998 ZT16-19 23.05 23.05 23.05 ZT20-23 22.45 22.45 22.45