What is accuracy?

How close a measurement is to its true value, influenced by the systematic and random errors of that measurement.

What is precision?

How close a set of repeated measurements are to one another but not the true value, influenced by the random errors of those measurements.

What are base units?

The set of seven basic measures from which all other SI units can be derived.

What is estimation?

Making a reasonable approximation of a value in order to check a calculation or make a quick comparison to another value.

What is random error?

The unpredictable variation in a measurement. These can be reduced by taking many repeated measurements and calculating their mean.

What is repeatability?

An experiment is said to be repeatable if the same person with the same equipment obtains the same result when doing the same experiment a number of times, over a short time period.

What is reproducibility?

An experiment is said to be reproducible if different people with different equipment, measuring the same quantity, get a similar result.

What is resolution?

The smallest interval that a given measuring device can measure.

What is systematic error?

A consistent shift in readings causing a deviation from the true value. This shift is due to the equipment or method being used and cannot be reduced by repeated measurements.

What is uncertainty?

The range of values that could reasonably contain the true value of a measurement, based on the confidence an experimenter has about their result.