condition mean min max ZT0-3 18.455436 18.455436 18.455436 ZT4-7 13.904119000000001 13.904119000000001 13.904119000000001 ZT8-11 15.981962499999998 15.981962499999998 15.981962499999998 ZT12-15 26.5184845 26.5184845 26.5184845 ZT16-19 18.772432000000002 18.772432000000002 18.772432000000002 ZT20-23 22.000585 22.000585 22.000585