condition mean min max ZT0-3 15.455188 15.455188 15.455188 ZT4-7 18.782819500000002 18.782819500000002 18.782819500000002 ZT8-11 15.523603999999999 15.523603999999999 15.523603999999999 ZT12-15 15.157491499999999 15.157491499999999 15.157491499999999 ZT16-19 17.4801585 17.4801585 17.4801585 ZT20-23 16.257295 16.257295 16.257295