accuracy vs. precision?

[Fat Tone]

I spent 10 years working at the UK's National Physical Laboratory.

Here's how we defined it:

"Accuracy is a qualitative term relating the mean of the measurements to the true value, while precision is representative of the spread of these measurements. Even when we are precise and accurate, there will still be some uncertainty in our measurements. When the uncertainty of a measurement is evaluated and stated, then the fitness of purpose for a particular application can be properly understood."

(from http://www.npl.co.uk/npl/publication...ertainty5.html - some good diags there too)

T.

[KvHagedorn]

I detest the use of words like "qualitative" and turning verbs into nouns to make things particularly confusing. The ability to speak bullshitese does not make one's ideas more relevant.

As I said.. there is no such thing as an ACCURATE measurement, unless you are measuring by absolute units of the thing measured, such as three apples. If you ask how many grams of apples there are though, there is no accurate answer, because there is always another level of precision to pursue (that is, there are an infinite number of decimal places one could use to attain ever more precise measurments of the mass of these three apples.)

[Wombat]

I don't know. There are a lot of "verbings" that I don't like, but "qualitative" is a very useful word to me. Qualitative analysis, and its counterpart, quantitative analysis, are specific scientific methods.

[KvHagedorn]

Alright.. please define the word in a way that makes real sense.

[Novdid]

Originally posted by agallag
Ok then... uh... is my postcount 1711, or 1451.938744237475234985?

I've got to get movin', you're closing in fast I say!!!