Statistics / Deming

["Andy Gough, x4-2906, pager 513, CH2-59" <AGOUGH%FAB6@sc.intel.com>]

>Date: Fri, 15 Sep 89 11:40:28 -0400 (EDT)
>From: Alan William Hensel <ah1s+@andrew.cmu.edu>
>Subject: Re: 3" CD
>
>
>8 cm, exactly. 
>
>And those 5-inches, they're 12 cm, exactly.
>
>Go metric.
>
>-al+

Nothing is exact.  Every process has natural variation that you cannot
control.  So those CD's are specified with a +/- variation in the 
diameter--it could only be a few microns, but it is there.  You can use
statistics to study the natural variation in your process and insure
that you don't fail your specification very often.

Go statistical.

-andy