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DEX Contour Plot
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Important factors and best settings have been derived via
the usual analysis approach. Important factors, in order of
impotance, were X3 (number of bands), X4 (arm length),
X1 (band height), X5 (stop angle), and weakly X2 (start angle).
Some interactions (especially X3*X4) were also important. Best
settings included:
- For Y = 30: (xx) or augment the (yy) data
- For Y = 60: augment the (xx) data
- For Y = 90: (0 0 + 0 0)
Anomalies existed in the data. Plots revealed higher
variability for X3 = +1 than for X3 = -1 implying a serious
violation of the constant
variation assumption for least squares fitting.
Cross-validation revealed poor-quality fits for the X3 = +1 data,
especially at the X3 = +1 pseudo-center point; hence interpolation
was suspect. Corrective action is thus suggested:
- Transformations
of Y (to correct non-constant variation).
- Subset Analyses (to correct poor-fitting regions).
The following section carries out such a corrected analysis.
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