condition mean min max ZT0-3 5.377945 5.377945 5.377945 ZT4-7 3.62849 3.62849 3.62849 ZT8-11 4.630655 4.630655 4.630655 ZT12-15 2.7915900000000002 2.7915900000000002 2.7915900000000002 ZT16-19 2.5904800000000003 2.5904800000000003 2.5904800000000003 ZT20-23 4.084875 4.084875 4.084875