condition mean min max ZT0-3 10.139734 10.139734 10.139734 ZT4-7 10.1916065 10.1916065 10.1916065 ZT8-11 8.588576 8.588576 8.588576 ZT12-15 8.948474000000001 8.948474000000001 8.948474000000001 ZT16-19 10.8084595 10.8084595 10.8084595 ZT20-23 9.776802 9.776802 9.776802