condition mean min max ZT0-3 9.298958 9.298958 9.298958 ZT4-7 9.0907265 9.0907265 9.0907265 ZT8-11 9.4828695 9.4828695 9.4828695 ZT12-15 8.537037999999999 8.537037999999999 8.537037999999999 ZT16-19 9.333920500000001 9.333920500000001 9.333920500000001 ZT20-23 9.720829 9.720829 9.720829