condition mean min max ZT0-3 3.2148766666666666 1.92827 4.136035 ZT4-7 2.499835 2.499835 2.499835 ZT8-11 7.419815 7.419815 7.419815 ZT12-15 8.3013025 8.213415000000001 8.38919 ZT16-19 6.70964 6.70964 6.70964 ZT20-23 5.298170000000001 5.298170000000001 5.298170000000001