condition mean min max ZT0-3 2.35 2.35 2.35 ZT4-7 2.8 2.8 2.8 ZT8-11 1.85 1.85 1.85 ZT12-15 1.9500000000000002 1.9500000000000002 1.9500000000000002 ZT16-19 5.35 5.35 5.35 ZT20-23 2.5 2.5 2.5