Either or both of the bounding ordinates may be zero; the top, in that case, meets the base at that extremity.
The sides of the trapezette are the " bounding ordinates "; their abscissae being xo and xo+H, where H is the breadth of the trapezette.
From a line drawn through 0 parallel to the ordinates) is equal to the mean distance (§ 32) of the trapezette from this axis; moments with regard to the central ordinate are therefore sometimes described in statistics as " moments about the mean."
The data are then either the bounding ordinates uo, ui, ...
U m _ i, u m of the strips, or their mid-ordinates 44.