condition mean min max ZT0-3 8.1 8.1 8.1 ZT4-7 9.8 9.8 9.8 ZT8-11 10.8 10.8 10.8 ZT12-15 14.55 14.55 14.55 ZT16-19 12.8 12.8 12.8 ZT20-23 15.35 15.35 15.35