The hinges are used to connect the moveable control surfaces of the aircraft to the fixed surfaces and allow smooth easy movement They may take several forms including hinge points, pinned hinges, "living" hinges, etc
the internal junctions bewteen the bulk of the pages and the boards (see also joints)
Letter values at depth 1/4, roughly the quartiles sometimes called fourth The Hinges are the endpoints of the box of a box and whisker plot
Part of the hardware of the frame The hinges attach to both the temple and front of the frame
The value of the lower hinge is approximately the first quartile, or 25th percentile The value of the upper hinge is approximately the third quartile, or 75th percentile The values of the hinges and quartiles may differ slightly because of differing computational conventions