condition mean min max ZT0-3 8.605562 8.605562 8.605562 ZT4-7 12.8396695 12.8396695 12.8396695 ZT8-11 10.9617605 10.9617605 10.9617605 ZT12-15 8.764748 8.764748 8.764748 ZT16-19 8.676736 8.676736 8.676736 ZT20-23 8.333115 8.333115 8.333115