Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: Significant figures - a Modest Proposal

On Mon, 30 Aug 1999, Leigh Palmer wrote:

[snip]
I don't believe precision relates to repeatability.

I'm not an expert on error analysis so I may be mistaken about this. If
so, I'd appreciate if someone would set me straight before I mislead all
of my students.

I'm not an expert either, but I think the example above is incorrect.
I can't even consult a standard reference, I'm afraid, but I would
probably do so before teaching this to a group of students.

I was able to find the "Glossary of Time and Frequency Terms" on a NIST
page <http://www.boulder.nist.gov/timefreq/glossary.htm>. In the glossary,
the following definitions are given:

Accuracy: The degree of conformity of a measured or calculated value to
its definition or with respect to a standard reference (see uncertainty).

Error: The difference of a measured value from its known true or correct
value (or sometimes from its predicted value).

Precision: The degree of mutual agreement among a series of individual
measurements. Precision is often, but not necessarily, expressed by the
standard deviation of the measurements.

Resolution: The degree to which a measurement can be determined is called
the resolution of the measurement. The smallest significant difference
that can be measured with a given instrument. For example, a measurement
made with a time interval counter might have a resolution of 10 ns.

Uncertainty: The limits of the confidence interval of a measured or
calculated quantity. NOTE: The probability of the confidence limits should
be specified, preferably as one standard deviation.

Anyone have any other references we can use?

----------------------------------------------------------
| Robert Cohen Department of Physics |
| East Stroudsburg University |
| bbq@esu.edu East Stroudsburg, PA 18301 |
| http://www.esu.edu/~bbq/ (570) 422-3428 |
----------------------------------------------------------