condition mean min max ZT0-3 8.446746 8.446746 8.446746 ZT4-7 9.063111500000002 9.063111500000002 9.063111500000002 ZT8-11 10.6250875 10.6250875 10.6250875 ZT12-15 8.5084645 8.5084645 8.5084645 ZT16-19 10.225539 10.225539 10.225539 ZT20-23 10.765035999999998 10.765035999999998 10.765035999999998