Precision

From Wikipedia, the free encyclopedia

Precision has the following meanings:

1. In engineering, science, industry, and statistics, precision characterises the degree of mutual agreement among a series of individual measurements, values, or results — see accuracy and precision.
2. In computing, precision means one of the following:
   • the precision (number of digits) with which a value is expressed (e.g., the number of significant decimal digits or significant bits – a calculation which rounds to three digits is said to have a working precision or rounding precision of 3)
   • the units of the least significant digit of a measurement; for example, if a measurement is 17.130 meters then its precision is millimeters (one unit in the last place, or ulp, is 1 mm)
   • (in some programming languages and databases) the number of decimal places after the decimal point in a fixed-point number; to avoid confusion, this usage is best avoided.
3. With respect to a set of independent devices of the same design, precision is the ability of these devices to produce the same value or result, given the same input conditions and operating in the same environment (as defined by Federal Standard 1037C and MIL-STD-188).
4. With respect to a single device, put into operation repeatedly without adjustments, precision is the ability to produce the same value or result, given the same input conditions and operating in the same environment (as defined by Federal Standard 1037C and MIL-STD-188).
5. In information retrieval, precision is the percentage of documents returned that are relevant. This is often coupled with the recall measure. Together, the two scores are sometimes used to calculate the F1 Score.
6. In music, Precision is the official march of the Royal Military College of Canada.
7. In the game of contract bridge, Precision Club is a bidding system.

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