RE: Shewhart's Maximum Control

[Steven_S_Prevette@RL.gov]

>What is modeling, why is matching a distribution important, and how does it
help in 
>running a company?

Modeling is using something to represent something else.  I have a bedroom
full of N scale model trains, which models railroad operations in
northeastern Pennsylvania in 1970.  Cars are collected at industries, sorted
in yards, and made up into trains to be delivered to other industries.

A map is also a model (of the territory).  But, has been said before on the
DEN, a map is not the territory.

In the context of the DEN (and operations research), modeling is using a
mathematical representation for a company process.  Computer models can get
very sophisticated.  Dr. Shewhart and Dr. Deming found it sufficient to
collect some operational data, put it on a control chart, and model the
process on the control chart.  Models for companies are used for prediction
of future results.

Operations Researchers believe matching distributions to be very important.
Dr. Deming did not.  He felt the time-series was more important than the
distribution.  Control charts are not dependent upon the distribution,
unless you are trying to claim that the control limits represent
probabilities, or are a Six Sigma person trying to explain sigma as
analogous to a failure rate.


Steven S Prevette	
ASQ Certified Quality Engineer
Fluor Hanford ESH Planning and Performance
509-373-9371
steven_s_prevette@rl.gov
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