condition mean min max ZT0-3 8.27989 8.27989 8.27989 ZT4-7 7.645462500000001 7.645462500000001 7.645462500000001 ZT8-11 6.975868999999999 6.975868999999999 6.975868999999999 ZT12-15 7.362031 7.362031 7.362031 ZT16-19 7.3501985 7.3501985 7.3501985 ZT20-23 6.9035515 6.9035515 6.9035515