5.
Process Improvement
5.5. Advanced topics 5.5.9. An EDA approach to experimental design 5.5.9.9. Cumulative residual standard deviation plot


Cumulative residual standard deviation plot typically has a hockey stick appearance 
Proceeding left to right, as we add more terms to the model, the
cumulative residual standard deviation "curve" will typically decrease.
At the beginning (on the left), as we add largeeffect terms, the
decrease from one residual standard deviation to the next residual
standard deviation will be large. The incremental improvement
(decrease) then tends to drop off slightly. At some point the
incremental improvement will typically slacken off considerably.
Appearancewise, it is thus very typical for such a curve to have a
"hockey stick" appearance:


Stopping rule 
The cumulative residual standard deviation plot provides a visual
answer to the question:
