cumulative percentage curve A graphical plot in which size classes are plotted against the percentage frequency of the class plus the sum of the percentages in preceding size classes. When plotted on normal graph paper, the cumulative frequency curve resembles an S-shape. When plotted on a normal-probability scale, the cumulative percentage data appear in a series of straight-line segments, each with a different gradient.

cumulative percentage curve A graphical plot in which size classes are plotted against the percentage frequency of the class plus the sum of the percentages in preceding size classes. When plotted on normal graph paper, the cumulative frequency curve resembles an S-shape. When plotted on a normal-probability scale, the cumulative percentage data appear in a series of straight-line segments, each with a different gradient.