Modeling and Multivariate Methods - SAS

Chapter 24 Visualizing, Optimizing, and Simulating Response Surfaces 597
The Simulator
Figure 24.46 Spec Limits in the Prediction Profiler
spec limit
mean
Defect Rate
report appears
Look at the histogram for Abrasion. The lower spec limit is far above the distribution, yet the Simulator is
able to estimate a defect rate for it. This despite only having 5000 runs in the simulation. It can do this
rare-event estimation when you use a Normal weighted distribution.
Note that the Overall defect rate is close to the defect rate for ELONG, indicating that most of the defects
are in the ELONG variable.
To see this weighted simulation in action, click the Make Table button and examine the Weight column.
JMP generates extreme values for the later observations, using very small weights to compensate. Since the
Distribution platform handles frequencies better than weights, there is also a column of frequencies, which
is simply the weights multiplied by 10 12 .
The output data set contains a Distribution script appropriate to analyze the simulation data completely
with a capability analysis.
Simulating General Formulas
Though the profiler and simulator are designed to work from formulas stored from a model fit, they work
for any formula that can be stored in a column. A typical application of simulation is to exercise financial
models under certain probability scenarios to obtain the distribution of the objectives. This can be done in
JMP—the key is to store the formulas into columns, set up ranges, and then conduct the simulation.