condition mean min max ZT0-3 2.51788021675 0.7736401425 4.2621202910000004 ZT4-7 0.9804526675 0.8658900134999999 1.0950153215 ZT8-11 1.0226708675 0.7595760520000001 1.2857656830000002 ZT12-15 2.7397714777499997 1.8599452469999997 3.6195977084999997 ZT16-19 1.6950699135 1.5445857495 1.8455540775000001 ZT20-23 2.0265291477500003 1.9199551325000002 2.1331031630000004