condition mean min max ZT0-3 7.0 7.0 7.0 ZT4-7 8.8 8.8 8.8 ZT8-11 9.3 9.3 9.3 ZT12-15 34.05 34.05 34.05 ZT16-19 11.95 11.95 11.95 ZT20-23 17.35 17.35 17.35