condition mean min max ZT0-3 1.1291489757500002 0.51448049 1.7438174615000002 ZT4-7 3.2625582719999997 2.939981783 3.585134761 ZT8-11 3.94403129325 3.0357286075000003 4.852333979 ZT12-15 5.666282274 4.7924457490000005 6.540118799 ZT16-19 5.289898875 4.7347640879999995 5.845033662 ZT20-23 7.30282190525 6.697057732499999 7.908586078000001