condition mean min max ZT0-3 2.440040833333333 0.9343675 4.4709699999999994 ZT4-7 0.3110455 0.3110455 0.3110455 ZT8-11 0.8789285 0.8789285 0.8789285 ZT12-15 4.4260125 2.2414199999999997 6.610605 ZT16-19 10.2866 10.2866 10.2866 ZT20-23 9.379625 9.379625 9.379625