Page 163 - Six Sigma Demystified

144 Six SigMa DemystifieD

• Goodness- of- fit tests help to verify the statistical distributions assumed in
the various statistical tools.

• Work breakdown structure helps to break down a problem into its potential
components, to be addressed in the improve stage.

Determining­Process­Drivers

• Design of experiments, factorial designs, and evolutionary operations help to
define efficient data- collection experiments.
• Regression analysis, residuals analysis, and scatter diagrams help to identify
significant process factors.
• Transformations help to stabilize variance or calculate meaningful re-
sponses.
• Interaction plots help to graphically depict the relationship between two
factors’ effect on the mean.
• Process decision program charts help to understand root causes of problems.

In addition, the consensus- building tools noted at the end of the define stage
(see Chapter 4) are also applied as needed.