5.
Process Improvement
5.5. Advanced topics 5.5.9. An EDA approach to experimental design 5.5.9.10. DOE contour plot


Corresponds to ideal optimum value  The optimal curve is the curve on the contour plot that corresponds to the ideal optimum value.  
Defective springs example  For the defective springs data, we search for the Y = 100 contour curve. As determined in the steepest ascent/descent section, the Y = 90 curve is immediately outside the (+, +) point. The next curve to the right is the Y = 95 curve, and the next curve beyond that is the Y = 100 curve. This is the optimal response curve. 