condition mean min max ZT0-3 3.464655 3.464655 3.464655 ZT4-7 2.480715 2.480715 2.480715 ZT8-11 2.613355 2.613355 2.613355 ZT12-15 2.346055 2.346055 2.346055 ZT16-19 3.59456 3.59456 3.59456 ZT20-23 3.9592549999999997 3.9592549999999997 3.9592549999999997