condition mean min max ZT0-3 4.435195 4.435195 4.435195 ZT4-7 3.613015 3.613015 3.613015 ZT8-11 2.75904 2.75904 2.75904 ZT12-15 3.27612 3.27612 3.27612 ZT16-19 4.64787 4.64787 4.64787 ZT20-23 4.2741 4.2741 4.2741