condition mean min max ZT0-3 23.093371 23.093371 23.093371 ZT4-7 24.715221 24.715221 24.715221 ZT8-11 29.744911 29.744911 29.744911 ZT12-15 27.0274925 27.0274925 27.0274925 ZT16-19 34.666439999999994 34.666439999999994 34.666439999999994 ZT20-23 28.727663 28.727663 28.727663