Accuracy
A measurement result is this if it is judged to be close to the true value. It is a quality denoting the closeness of agreement between measurement and true value – it cannot be quantified and is influenced by random and systematic errors
Precise
When values cluster closely together
True value
The value that would have been obtained in an ideal measurement – with the exception of a fundamental constant the this is considered unknowable.
Resolution
The smallest measuring interval and the source of uncertainty in a single reading.
Error
The difference between the measurement result and the true value if a true value is thought to exist. This is not a mistake in the measurement. Can be due to both systematic and random effects.
Uncertainty
The interval within which the true value can be considered to lie with a given level of confidence or probability – this can be estimated by considering the instruments and the method and will usually be expressed as a range such as 20°C ± 2°C.
