RE: Statistical Control and Purpose

[Steven_S_Prevette@RL.gov]

>Does all nature tend toward a chaotic state? What do we mean by
"chaotic state"?

I personally believe that "chaos" implies that the system is not
predictable, and there is no pattern in the system.  This is slightly
different ("worse") than "random", which on the macro level is predictable.
An example is flipping a coin, which is random, but not chaotic.  I cannot
predict the result of the next coin flip, but I can predict that in the long
run the percentage of heads will tend towards 50%.  In chaos, I cannot state
even what the long run percentage will be.  Perhaps the coin explodes before
it hits the ground.

>Does nature not bring about limited change on  the basis of managing
diversity (variation)?

Most results of random variation (genetic mutation) were not beneficial to
the offspring.  A few were and survived to perpetuate.  That is, if you
believe the theory of evolution.

>Would we not have had gills and frog legs and tree bark for skin long
ago were it not for the limited diversity (variation) allowed or
controlled by our genetic makeup?

Er... I guess those mutations that could have accomplished that did not
survive

>What does one do with the Central limit theorem?

Not much.  The theory of control charts are based upon the Tchebychev
Inequality, not the central limit theorm.

>What of the funnel experiment? Does it not provide rationale for NOT
taking action, fearing tampering?

The actions taken during the funnel experiment were such that variation
increased.  However, there are certain actions, like putting rubber cement
on the table, and lowering the height of the funnel above the table, that
would accomplish a decrease in variation.  PDSA cycle evaluation would tell
you which actions were leading to increased variation, and which were
decreasing it.

Steve Prevette
ESH Planning and Performance
Fluor Hanford, A Fluor Global Services Company
ASQ Certified Quality Engineer
steven_s_prevette@rl.gov
509-373-9371
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