Figure 7

Graphical depiction of three possible interactions between predictor terms X1 and X2 (AND, OR, and XOR) that can be encoded by the design matrix Z. Values of β· Z range from 0 (red) to 1 (white). The interactions are encoded by specific linear combinations of X1, X2 and min(X1, X2), using the coefficients (three elements in the vector β) for the individual components (Table 2).