condition mean min max ZT0-3 3.85 3.85 3.85 ZT4-7 1.6 1.6 1.6 ZT8-11 3.9 3.9 3.9 ZT12-15 3.1 3.1 3.1 ZT16-19 1.9500000000000002 1.9500000000000002 1.9500000000000002 ZT20-23 3.25 3.25 3.25