Taguchi’s Orthogonal Array Experiment 489 18 13 Porosity 8 3 1 2 A A G D B E 17 14 Porosity 11 8 5 1 2 1 2 1 2 1 2 1 2 Figure 13.3 Main-effects plots—data means for porosity. 20 Yield 15 10 1 2 3 A Figure 13.4 Main-effects plot—data means for yield.