condition mean min max ZT0-3 5.91977 5.91977 5.91977 ZT4-7 4.96694 4.96694 4.96694 ZT8-11 3.6800100000000002 3.6800100000000002 3.6800100000000002 ZT12-15 5.471535 5.471535 5.471535 ZT16-19 7.68211 7.68211 7.68211 ZT20-23 8.3233 8.3233 8.3233