condition mean min max ZT0-3 11.3 11.3 11.3 ZT4-7 14.3 14.3 14.3 ZT8-11 21.3 21.3 21.3 ZT12-15 5.8 5.8 5.8 ZT16-19 12.5 12.5 12.5 ZT20-23 22.55 22.55 22.55