condition mean min max ZT0-3 2.3 2.3 2.3 ZT4-7 2.8 2.8 2.8 ZT8-11 3.25 3.25 3.25 ZT12-15 3.15 3.15 3.15 ZT16-19 25.900000000000002 25.900000000000002 25.900000000000002 ZT20-23 3.6500000000000004 3.6500000000000004 3.6500000000000004