condition mean min max ZT0-3 5.6 5.6 5.6 ZT4-7 8.0 8.0 8.0 ZT8-11 34.95 34.95 34.95 ZT12-15 33.45 33.45 33.45 ZT16-19 31.5 31.5 31.5 ZT20-23 48.95 48.95 48.95