RE: Statistical Software

[Steven_S_Prevette@RL.gov]

Q:  What different types of software is everyone using out there?  

I use Excel 97 spreadsheet as is, no extra additions.  I write my own
formulae for averages and control limits.

I do this for a couple of reasons:
	1.  It is inexpensive.  Excel 97 is part of the baseline software
everybody's computer gets in my company.  I do not have to plead for any
"extra" money to do SPC.  Many want to disregard SPC as "expensive".

	2.  I have a fear (and so did Dr. Deming) of the "unmanned
computer".  All one has to do is enter the data, and voila, a control chart
appears.  Wallpaper the walls with them!  But does anyone understand the
theory of how they were made?  How to use them?

	3.  Even with knowledge of the theory, I distrust many of the
"canned" packages.  You don't know what internal assumptions are being made
in the software.  What algorithms are being used to make the average
calculations?  The control limit calculations?  For example, some
pseudo-random number generators in commercial software are notoriously bad.
I would rather write my own formula (which is a one-liner).

	4.  Determination of proper sub-groupings and proper baseline time
intervals is not a decision that these software can do.  This still requires
the human to do.

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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