condition mean min max ZT0-3 23.579456 23.579456 23.579456 ZT4-7 11.528837 11.528837 11.528837 ZT8-11 9.6527605 9.6527605 9.6527605 ZT12-15 11.380780000000001 11.380780000000001 11.380780000000001 ZT16-19 10.1259575 10.1259575 10.1259575 ZT20-23 9.545765 9.545765 9.545765