condition mean min max ZT0-3 11.903035 5.315755 16.051099999999998 ZT4-7 2.662455 2.662455 2.662455 ZT8-11 0.3687435 0.3687435 0.3687435 ZT12-15 0.53887175 0.455602 0.6221415 ZT16-19 1.1723409999999999 1.1723409999999999 1.1723409999999999 ZT20-23 3.501835 3.501835 3.501835