condition mean min max ZT0-3 3.260155 3.260155 3.260155 ZT4-7 2.6743550000000003 2.6743550000000003 2.6743550000000003 ZT8-11 1.374465 1.374465 1.374465 ZT12-15 1.1638950000000001 1.1638950000000001 1.1638950000000001 ZT16-19 2.976635 2.976635 2.976635 ZT20-23 3.21413 3.21413 3.21413