condition mean min max ZT0-3 279.232466 279.232466 279.232466 ZT4-7 294.5508705 294.5508705 294.5508705 ZT8-11 291.95580099999995 291.95580099999995 291.95580099999995 ZT12-15 309.981764 309.981764 309.981764 ZT16-19 391.48551050000003 391.48551050000003 391.48551050000003 ZT20-23 376.68874800000003 376.68874800000003 376.68874800000003