Visual Six Sigma: Making Data Analysis Lean

8.7. Revising Knowledge

Having constructed models for MFI and CI and having identified the relevant Hot Xs, Carl and his team are ready to proceed to the Revise Knowledge step of the Visual Six Sigma Data Analysis Process. They will identify optimal settings for the Hot Xs, evaluate process behavior relative to variation in the Hot Xs using simulation, and run confirmatory trials to verify improvement.

8.7.1. Determining Optimal Factor Level Settings

With both prediction formulas saved to the data table, Carl is ready to find settings for the Xs that will simultaneously optimize MFI and CI. To find these optimal settings, Carl selects Graph > Profiler. He enters both prediction formulas as Y, Prediction Formula (Exhibit 8.68).

Figure 8.68. Launch Dialog for Profiler

Clicking OK displays the profiler report shown in Exhibit 8.69, and Carl immediately saves this script as Profiler. Carl thinks back to what he learned in his training. The idea is to think of each prediction formula as defining a response surface. The profiler shows cross sections, called traces, of both response surfaces, with the top row of panels corresponding to MFI and the second row corresponding to CI. The cross sections are given for the designated values of M%, Xf, SA, and Quarry. To explore various factor settings, the vertical red dotted lines can be moved by clicking and dragging, showing how the two ...