condition mean min max ZT0-3 18.2759 18.2759 18.2759 ZT4-7 15.5027 15.5027 15.5027 ZT8-11 13.32155 13.32155 13.32155 ZT12-15 14.02175 14.02175 14.02175 ZT16-19 16.680600000000002 16.680600000000002 16.680600000000002 ZT20-23 17.982349999999997 17.982349999999997 17.982349999999997