condition mean min max ZT0-3 2.5 2.5 2.5 ZT4-7 2.4 2.4 2.4 ZT8-11 35.1 35.1 35.1 ZT12-15 5.300000000000001 5.300000000000001 5.300000000000001 ZT16-19 4.0 4.0 4.0 ZT20-23 3.65 3.65 3.65