condition mean min max ZT0-3 4.392055 4.392055 4.392055 ZT4-7 2.700495 2.700495 2.700495 ZT8-11 3.0674900000000003 3.0674900000000003 3.0674900000000003 ZT12-15 3.335495 3.335495 3.335495 ZT16-19 4.28479 4.28479 4.28479 ZT20-23 5.142094999999999 5.142094999999999 5.142094999999999