condition mean min max ZT0-3 11.8 11.8 11.8 ZT4-7 8.5 8.5 8.5 ZT8-11 15.7 15.7 15.7 ZT12-15 8.8 8.8 8.8 ZT16-19 9.95 9.95 9.95 ZT20-23 8.2 8.2 8.2