condition mean min max ZT0-3 7.671887 7.671887 7.671887 ZT4-7 7.597277500000001 7.597277500000001 7.597277500000001 ZT8-11 7.406617 7.406617 7.406617 ZT12-15 7.768791 7.768791 7.768791 ZT16-19 7.998875 7.998875 7.998875 ZT20-23 8.1849885 8.1849885 8.1849885