condition mean min max ZT0-3 10.046624999999999 10.046624999999999 10.046624999999999 ZT4-7 7.55673 7.55673 7.55673 ZT8-11 8.817085 8.817085 8.817085 ZT12-15 7.8160799999999995 7.8160799999999995 7.8160799999999995 ZT16-19 9.717625 9.717625 9.717625 ZT20-23 9.44827 9.44827 9.44827