condition mean min max ZT0-3 7.953747 7.953747 7.953747 ZT4-7 7.7475385 7.7475385 7.7475385 ZT8-11 7.1248725 7.1248725 7.1248725 ZT12-15 7.9442325 7.9442325 7.9442325 ZT16-19 8.581508 8.581508 8.581508 ZT20-23 8.0260855 8.0260855 8.0260855