what is precision

Precision is a measure of how close two or more measurements are to each other, regardless of whether those measurements are accurate or not. It is a description of random errors and a measure of statistical variability. Precision is independent of accuracy, which is a measure of how close a given set of measurements are to their true value. In other words, accuracy is a description of only systematic errors, a measure of statistical bias of a given measure of central tendency. High precision means that the measured values are similar to each other, while low precision means that they are scattered. Precision is often expressed in terms of the number of decimal places or significant figures in a measurement.