condition mean min max ZT0-3 29.936438 29.936438 29.936438 ZT4-7 26.5220585 26.5220585 26.5220585 ZT8-11 30.6013485 30.6013485 30.6013485 ZT12-15 30.009737 30.009737 30.009737 ZT16-19 32.29005 32.29005 32.29005 ZT20-23 26.8099905 26.8099905 26.8099905