condition mean min max ZT0-3 9.067028 9.067028 9.067028 ZT4-7 8.832396 8.832396 8.832396 ZT8-11 9.0864185 9.0864185 9.0864185 ZT12-15 8.691578 8.691578 8.691578 ZT16-19 9.466772 9.466772 9.466772 ZT20-23 8.359161 8.359161 8.359161