condition mean min max ZT0-3 1.7750248000000002 1.2151469590000001 2.3349026410000002 ZT4-7 3.0753871444999996 2.7613728454999995 3.3894014434999997 ZT8-11 2.7971573614999996 2.7216650634999997 2.8726496594999995 ZT12-15 2.6940708185 2.670955573 2.717186064 ZT16-19 1.45126131175 1.412277471 1.4902451525 ZT20-23 3.3549133514999996 1.6726875665 5.0371391365