pg_0021

Process Improvement

5.2.

Assumptions

We should

check the

engineering

and

model-building

assumptions

that are made

in most DOE's

In all model building we make assumptions, and we also require

certain conditions to be approximately met for purposes of estimation.

This section looks at some of the engineering and mathematical

assumptions we typically make. These are:

Are the measurement systems capable for all of your

responses.

Is your process stable.

Are your responses likely to be approximated well by simple

polynomial models.

Are the residuals (the difference between the model predictions

and the actual observations) well behaved.

5.2. Assumptions

http://www.itl.nist.gov/div898/handbook/pri/section2/pri2.htm [5/7/2002 4:01:43 PM]