Otto:
Couldn't resist this (not that it's not an electrical joke thread... --
although we could induct "the other group" and really give this
discussion a positive charge...)
As I have been working on the latest project and turning over the design
in my mind I have been trying to draw a bead on this "accuracy and
precision thing". Not to put too fine a point on it but one can grind on
the issues until you develop the skill to put a finer point on your
instruments of operation. In other words if one is going cut to the
quick, and not shave the truth, or skew the situation (lest it spiral
out of control), it would be best to take harbor in a comfy cove and
contemplate the issues carefully. Anything else would be but a finial on
a turners philosophy in addressing the issues with sufficient sharpness.
If that is clear, read on.
ottomatic wrote:
for those who care
precise is an absolute measure ie .005 inches
accurate is a percentage reference ie .005 inches per foot
Not necessarily. IMO It would inaccurate and imprecise to say the above..
First: "i.e." Is I believe -- "id est" (That is to say -- "That is") in
Latin as I recall -- pretty foggy on my Latin these days and too lazy to
look -- how is that for an imprecise answer.. LOL i.e. -- the "periods"
count and "ie" is an inaccurate depiction of the contraction.
)
So If I may be so bold this could be better:
**
... accurate is a percentage reference -- e.g. The measurement is 1.02
feet - precise to two places and accurate within +/- .005 inches. If one
is describing a single measurement. (An observation.)
Here we can/should/might give a precise amount of _an estimate of_ the
observable error. Since it is a measurement.
or
The measurement is 1.02 foot - precise to two places and accurate within
2% per foot of length after all applicable calculations. If one is
describing a what could be called a calculation method used to arrive at
a figure. This is assuming we had used multiplication or division to
arrive at this number.
If we only used addition or subtraction, it would be best (more
acceptable) to state a +/- error figure. (Not necessarily symmetric as
in: within +.05 inches, and within -.1 inches)
Note that statistical methods would use all the arithmetic operation
classes and we would therefore be compelled to say something of this
nature in other situations:
e.g.
I asked the classs to measure a 4.50 inch stick of wood and record that
number along with their estimated error. After analysis I determined
that they were with .05 inches of the correct answer 80% of the time and
had a greater error the remaining 20% of the time. In other words the
class can be counted on to take a measurement with an accuracy of 1.5%
in a similar situation -- at least 80 %of the time.
**
The above would -- I believe -- be more correct. Assuming I was taught
correctly -- and I make no guarantees -- especially after considering my
past professors carefully, and considering my scholarly record -- which
was disgraceful at best.
....Since one is describing a particular example (for e.g.) -- not a
stating a general principle (Or is it principal? hmmm LOL) So therefore
it was an inaccurate depiction of the principle, and imprecise thinking.
And other far more knowledgeable people who frequent this group could
of course pick me to tiny pieces.
The point is that is quite difficult to precisely describe this issue
without a lot of thought - and requires _far_ too many words to make it
fun (* or accurate).
And now I think I will run rather than waiting for a well deserved shot,
and a cranky reply. ROTFL
And now -- back to the lathe.
ergo it would be imprecise to describe a language as inaccurate
What can I say to that... ?
Ottoaprentice wordsmint
"Arch" wrote in message
...
Will, be careful. I think you got it right, but you might get your nose
tweaked for saying "precise" if you meant "accurate". I did once and I
still don't understand the difference. Or care! I think it has to do
with repeatability. Maybe somebody will set both of us 'cynics' straight
(ie.without curves or angles) G)
Turn to Safety, Arch
Fortiter
http://community.webtv.net/almcc/MacsMusings
--
Will
Occasional Techno-geek