condition mean min max ZT0-3 16.449591 16.449591 16.449591 ZT4-7 14.055544000000001 14.055544000000001 14.055544000000001 ZT8-11 12.5854715 12.5854715 12.5854715 ZT12-15 12.879164 12.879164 12.879164 ZT16-19 12.487647500000001 12.487647500000001 12.487647500000001 ZT20-23 13.215367 13.215367 13.215367