Question

Define the terms accuracy and precision. Give examples which illustrate the difference between terms.

Answer 1

Accuracy: Generally there are two common definitions are there for the term accuracy. In math, science, and engineering, accuracy refers to how close a measurement is to the true value. In other words, accuracy refers to the closeness of a measured value to a standard or known value.

According to ISO (International Organization for Standardization) accuracy refers to a measurement with both true and consistent results. The ISO definition means an accurate measurement has no systematic error and no random error.

Precision: Precision means how consistent results are when measurements are repeated. In other words, Precision refers to the closeness of two or more measurements to each other. Precise values differ from each other because of random error, which is a form of observational error.

Examples of Accuracy and Precision:

Just think of accuracy and precision in terms of a basketball player. Now, if a player always makes a basket, even though he hits different portions of the rim, then he has a high degree of accuracy. But if he doesn't make many baskets, but always strikes the same portion of the rim, he has a high degree of precision. Again, if a player who throws free throws that always make the basket exactly same way has a high degree of both accuracy and precision.