condition mean min max ZT0-3 13.7 13.7 13.7 ZT4-7 10.3 10.3 10.3 ZT8-11 6.9 6.9 6.9 ZT12-15 14.2 14.2 14.2 ZT16-19 8.3 8.3 8.3 ZT20-23 19.05 19.05 19.05