condition mean min max ZT0-3 8.2 8.2 8.2 ZT4-7 4.4 4.4 4.4 ZT8-11 5.15 5.15 5.15 ZT12-15 8.3 8.3 8.3 ZT16-19 5.7 5.7 5.7 ZT20-23 18.9 18.9 18.9