condition mean min max ZT0-3 16.1 16.1 16.1 ZT4-7 4.9 4.9 4.9 ZT8-11 7.25 7.25 7.25 ZT12-15 13.7 13.7 13.7 ZT16-19 3.3 3.3 3.3 ZT20-23 10.75 10.75 10.75