condition mean min max ZT0-3 13.811831 13.811831 13.811831 ZT4-7 9.7136125 9.7136125 9.7136125 ZT8-11 11.557438000000001 11.557438000000001 11.557438000000001 ZT12-15 15.034655 15.034655 15.034655 ZT16-19 21.289015 21.289015 21.289015 ZT20-23 19.629586 19.629586 19.629586