condition mean min max ZT0-3 6.6423325 6.276125 7.00854 ZT4-7 8.629215 8.629215 8.629215 ZT8-11 9.25631 9.25631 9.25631 ZT12-15 0 0 0 ZT16-19 8.31736 8.31736 8.31736 ZT20-23 9.321815 9.321815 9.321815