5.
Process Improvement
5.6.
Case Studies
5.6.1.
Eddy Current Probe Sensitivity Case Study
5.6.1.7.

Intermediate Conclusions


Important Factors

Taking stock from all of the graphical and quantitative analyses of
the previous sections, we conclude that X1 (number of turns)
is the most important engineering factor affecting sensitivity,
followed by X2 (wire distance) as next in importance, followed
then by some less important interactions and X3 (wire gauge).

Best Settings

Also, from the various analyses, we conclude that the best design
settings (on the average) for a highsensitivity detector are
that is
number of turns = 180,
winding distance = 0.38, and
wire gauge = 48.

Can We Extract More From the Data?

Thus, in a very real sense, the analysis is complete. We have
achieved the two most important stated goals of the experiment:
 gaining insight into the most important factors, and
 ascertaining the optimal production settings.
On the other hand, more information can be squeezed from the data,
and that is what this section and the remaining sections address.
 First of all, we focus on the problem of taking the ranked
list of factors and objectively ascertaining which factors
are "important" versus "unimportant".
 In a parallel fashion, we use the subset of important factors
derived above to form a "final" prediction equation that is good
(that is, having a sufficiently small residual standard
deviation) while being parsimonious (having a small number of
terms), compared to the full model, which is perfect (having a
residual standard deviation = 0, that is, the predicted
values = the raw data), but is unduly complicated (consisting
of a constant + 7 terms).
