condition mean min max ZT0-3 5.624061666666667 5.40437 5.980055 ZT4-7 2.94753 2.94753 2.94753 ZT8-11 1.885195 1.885195 1.885195 ZT12-15 2.2676175 2.02709 2.508145 ZT16-19 1.543715 1.543715 1.543715 ZT20-23 2.9866900000000003 2.9866900000000003 2.9866900000000003