condition mean min max ZT0-3 5.95 5.95 5.95 ZT4-7 9.6 9.6 9.6 ZT8-11 23.0 23.0 23.0 ZT12-15 7.5 7.5 7.5 ZT16-19 8.7 8.7 8.7 ZT20-23 4.9 4.9 4.9