condition mean min max ZT0-3 47.7 47.7 47.7 ZT4-7 9.6 9.6 9.6 ZT8-11 19.3 19.3 19.3 ZT12-15 25.1 25.1 25.1 ZT16-19 21.9 21.9 21.9 ZT20-23 38.25 38.25 38.25