condition mean min max ZT0-3 28.267088 28.267088 28.267088 ZT4-7 18.779679 18.779679 18.779679 ZT8-11 17.545977 17.545977 17.545977 ZT12-15 20.998463 20.998463 20.998463 ZT16-19 15.738559500000001 15.738559500000001 15.738559500000001 ZT20-23 15.468664 15.468664 15.468664