RESIDUAL MASS DIAGRAM

A diagram or graph plotted with rectangular coordinates, with each ordinate equal to (a) the sum of all preceding quantities in the series up to a given point, minus (b) the arithmetic mean of the series times the number of quantities in the series up to a given point, and the corresponding abscissa representing time, number of the item in the series, etc. A general upward slope of a section of such a graph indicates that the terms in the series within the section are, in general, in excess of the average for the series, and vice versa. The diagram is used in determining cyclic variation of quantities such as precipitation.