condition mean min max ZT0-3 7.224685 7.224685 7.224685 ZT4-7 5.446585 5.446585 5.446585 ZT8-11 5.223325 5.223325 5.223325 ZT12-15 5.897715 5.897715 5.897715 ZT16-19 8.078009999999999 8.078009999999999 8.078009999999999 ZT20-23 7.34718 7.34718 7.34718