condition mean min max ZT0-3 13.085728333333334 5.295135 17.0054 ZT4-7 4.149955 4.149955 4.149955 ZT8-11 2.21356 2.21356 2.21356 ZT12-15 3.0320975 2.79425 3.269945 ZT16-19 4.713605 4.713605 4.713605 ZT20-23 12.25907 12.25907 12.25907