condition mean min max ZT0-3 14.517399999999999 14.517399999999999 14.517399999999999 ZT4-7 7.8156300000000005 7.8156300000000005 7.8156300000000005 ZT8-11 5.39317 5.39317 5.39317 ZT12-15 8.019955 8.019955 8.019955 ZT16-19 15.3535 15.3535 15.3535 ZT20-23 19.55885 19.55885 19.55885