condition mean min max ZT0-3 2.95 2.95 2.95 ZT4-7 1.3 1.3 1.3 ZT8-11 20.4 20.4 20.4 ZT12-15 2.8000000000000003 2.8000000000000003 2.8000000000000003 ZT16-19 0.9500000000000001 0.9500000000000001 0.9500000000000001 ZT20-23 1.65 1.65 1.65