Russ;
Yes, that type of data gives us grey hairs trying to find out the cause. My
approach to finding the problem is to ask myself "What is different between
yesterday and today?" Temperature is always pretty high on my list of "usual
suspects".
Regards, Neil Tucson, AZ
-----Original Message-----
From: Russel Mack [mailto:rtmack@concentric.net]
Sent: Saturday, May 10, 2003 11:33 AM
To: Albaugh, Neil; 'John Goodman'; land-speed@autox.team.net
Subject: RE: The concept of Data?
Neil:
I have a class that I sometimes give for instrument techs that uses exactly
this analogy. Russ, #1226B
PS- what I'm most concerned about is the "gun" that shoots a tight group in
the first ring one day, and a tight group in the fourth ring the next day.
You can't hunt with a gun like that. And you can't improve your LSR effort
with that kind of data, either.
-----Original Message-----
From: Albaugh, Neil [mailto:albaugh_neil@ti.com]
Sent: Friday, May 09, 2003 5:24 PM
To: 'Russel Mack'; 'John Goodman'; 'land-speed@autox.team.net'
Subject: RE: The concept of Data?
Russ, et al;
One way this difference between "accuracy" and "precision" can be
illustrated is to visualize a bulls-eye target.
Lots of holes tightly grouped over in one corner of the target represents
"precision"; Holes all over the target but centered on the bulls-eye is
"accuracy". If the measurement has precision but not accuracy, the error can
be calibrated out. The only way to deal with accuracy without precision is
to average a large number of samples; if the error is truly random, it will
average to zero.
Regards, Neil Tucson, AZ
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