condition mean min max ZT0-3 18.127237 18.127237 18.127237 ZT4-7 16.419817 16.419817 16.419817 ZT8-11 18.968661 18.968661 18.968661 ZT12-15 15.201903 15.201903 15.201903 ZT16-19 15.732115499999999 15.732115499999999 15.732115499999999 ZT20-23 16.6846155 16.6846155 16.6846155