condition mean min max ZT0-3 3.853511833333333 1.3253655 7.501655 ZT4-7 5.8014 5.8014 5.8014 ZT8-11 2.1084199999999997 2.1084199999999997 2.1084199999999997 ZT12-15 0.698801 0.0 1.397602 ZT16-19 0.075636 0.075636 0.075636 ZT20-23 0.3509005 0.3509005 0.3509005