Definitions: 1. Measurements and Their Errors: Paper 1: Physics A Level AQA

Accuracy

A measure of how close a measurement is to the true value.

Precision

A measure of how close a measurement is to the mean value. It only gives an indication of the magnitude of random errors, not how close data is to the true value.

Random Error

Unpredictable variation between measurements that leads to a spread of values about the true value. Random error can be reduced by taking repeat measurements.

Systematic Error

Causes all readings to differ from the true value by a fixed amount. Systematic error cannot be corrected by repeat readings, instead a different technique or apparatus should be used.

Repeatable

The same experimenter can repeat a measurement using the same method and equipment and obtain the same value.

Reproducible

An experiment can be repeated by a different experimenter using a different method and different apparatus, and still obtain the same results.

Resolution

The smallest change in a quantity that causes a visible change in the reading that a measuring instrument records.

Uncertainty

The interval that a value is said to lie within, with a given level of confidence.