RE: Rule of thumb for SPC

[Alson Look <Alson.Look@e-tek.com>]

When you say run chart do you mean range chart?

1.  You should try to find out what the assignable cause is before you throw
any data out.  One of the purposes of the control chart is to learn about
the process.
2.  If the word run chart refers to range chart and almost all our data on
the xbar are outside the control limits you may want to examine how you are
rationally sampling.  You maybe looking at measurement error. 

Alson C H Look
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