Talk:Measurement

Precision

The definitions I've found for precision relate to the repeatability of a measurement. However, there appear to be at least two aspects of precision, one of which is not addressed by the repeatability criterion, and I'm not sure what it is called. It's related to the "significant figures" of a measurement, but I don't know if that's a formal name or not.

As an example, imagine an object 11.9 inches long, and a ruler with markings only at every inch, with no subdivisions. When the ruler is checked against a high-precision standard, the markings are found to be correct within 0.001 inch. The precision of the measurement can be made arbitrarily small, as good practice with the ruler will yield a result of 12 inches every single time. 10,000 repeat measurements will all be 12 inches, thus the length can be reported as 12.00 with a precision of 0.01, but this is wrong. A ruler with markings every tenth of an inch would clearly show the length of the measured object to be 11.9 inches. What property is there more of in the ruler with markings every tenth of an inch? Anthony Argyriou 15:12, 22 April 2007 (CDT)