condition mean min max ZT0-3 12.760911 12.760911 12.760911 ZT4-7 12.8781595 12.8781595 12.8781595 ZT8-11 13.707166 13.707166 13.707166 ZT12-15 11.7794585 11.7794585 11.7794585 ZT16-19 13.1657315 13.1657315 13.1657315 ZT20-23 12.824621 12.824621 12.824621