condition mean min max ZT0-3 6.012785 6.012785 6.012785 ZT4-7 4.203525 4.203525 4.203525 ZT8-11 2.728785 2.728785 2.728785 ZT12-15 4.14868 4.14868 4.14868 ZT16-19 5.868 5.868 5.868 ZT20-23 5.806895 5.806895 5.806895