condition mean min max ZT0-3 16.85 16.85 16.85 ZT4-7 2.8 2.8 2.8 ZT8-11 6.0 6.0 6.0 ZT12-15 6.95 6.95 6.95 ZT16-19 17.0 17.0 17.0 ZT20-23 4.25 4.25 4.25