condition mean min max ZT0-3 1009.987771 1009.987771 1009.987771 ZT4-7 1244.4618854999999 1244.4618854999999 1244.4618854999999 ZT8-11 936.0560459999999 936.0560459999999 936.0560459999999 ZT12-15 1003.631344 1003.631344 1003.631344 ZT16-19 851.9901165000001 851.9901165000001 851.9901165000001 ZT20-23 887.040798 887.040798 887.040798