condition mean min max ZT0-3 4.1 4.1 4.1 ZT4-7 2.6 2.6 2.6 ZT8-11 2.85 2.85 2.85 ZT12-15 5.85 5.85 5.85 ZT16-19 4.6 4.6 4.6 ZT20-23 22.15 22.15 22.15