[relevant quotes not elided]
Post by Peter Moylan Post by Athel Cornish-Bowden Post by J. J. Lodder Post by Athel Cornish-Bowden Post by J. J. Lodder
Some sources do give a Roman mile of 1 482 meter.
I don't think the 'true' Roman mile is known to that accuracy,
or that the Romans could reproduce it to that accuracy,
While we're being pedantic, I think you mean precision.
<outpedanting> I think you are wrong about that.
"In measurement of a set, accuracy refers to closeness of the
measurements to a specific value, while precision refers to the
closeness of the measurements to each other."
Farbeit from me to argue with Wikipêia, but the way I learned it was
"A Roman mile was about one and a half kilometres" is accurate but not
"A Roman mile was 1.3895319 kilometres" is very precise but not at all
Does anyone agree, or am I just spouting nonsense that not even "Spains
Harden" would be guilty of?
I agree with you. I'm not sure where that Wikipedia definition came
from, but it doesn't agree with what I understand the normal definition
to be. Perhaps it's used in some specialised field. Statistics, perhaps?
Nope, "The field of statistics, where the interpretation of measurements plays a central role, prefers to use the terms bias and variability instead of accuracy and precision: bias is the amount of inaccuracy and variability is the amount of imprecision. "
You should think instead of metrology. The field of measurements.
WP cite, again:
Accuracy has two definitions:
More commonly, it is a description of systematic errors,
a measure of statistical bias; low accuracy causes
a difference between a result and a "true" value.
ISO calls this trueness.
Alternatively, ISO defines accuracy as describing a combination of
both types of observational error above (random and systematic),
so high accuracy requires both high precision and high trueness.
Precision is a description of random errors, a measure of statistical variability.
See also ISO 5725-1 (dating to 1994) and the 2008 issue of the
"BIPM International Vocabulary of Metrology" (VIM), items 2.13 and 2.14.
(One of the first links on that page is
"Evaluation of measurement data - Guide to the expression of uncertainty in measurement:
JCGM 100:200 (GUM 1995 with minor corrections)
I would suspect that this is applicable to those measuring reagents
and to those analyzing xray diffraction data,
for just a couple of ways it might come close to some of the expertise
in this group.
(Not so much my expertise; I'm not even doing TDR these days,
and holding light sources up to a piano-sized spectrometer
or running a Kelvin probe are even more distant.
I do pay attention to free file space and to TOP's load measurements)