Display of multiple variable relationships

Abstract

A method for displaying the joint variation of two or more dependent numerical variables v.sub.1 and v.sub.2 with respect to a third, independent numerical variable v.sub.3. For each of a sequence of numerical values of v.sub.3, the coordinate pairs (v.sub.1 (v.sub.3), v.sub.2 (v.sub.3)) are displayed on a two-dimensional Cartesian graph of v.sub.1 versus v.sub.2. A cursor or other indicator is provided on this graph that identifies the numerical value of the third variable v.sub.3 at any of the original sequence of such values. The cursor position is continuously interpolated between two consecutive numerical values of v.sub.3, corresponding to continuous variation of v.sub.3 between these two consecutive numerical values. The joint variation of v.sub.1 and v.sub.2 is also displayed by provision of two univariate graphs that exhibit v.sub.1 and v.sub.2 separately as functions of the third variable v.sub.3, with a suitable cursor or other movable indicator associated with each graph. The joint variation of v.sub.1 and v.sub.2 is also displayed as a numerical table of the values of v.sub.1, v.sub.2 and v.sub.3, with a cursor indicating the current choice of value of the variable v.sub.3. The graph of v.sub.1 (v.sub.3) versus v.sub.2 (v.sub.3) may be provided with an overlay showing normal and/or abnormal ranges of the coordinate pair (v.sub.1, v.sub.2).