Precision refers to the closeness of two or more measurements to each other. Using the example above, if you weigh a given substance five times, and get 3.2 kg each time, then your measurement is very precise. Precision is independent of accuracy. You can be very precise but inaccurate, as described above.
The amount of variation that exists in the values of multiple measurements of the same factor. Greater precision means less variation between measurements. Measurement precision is not to be confused with measurement accuracy, which depends on the level of agreement between the measurement and a known standard.

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