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## A Scrapbook of Digital Signal Processing

### Measurement (Accuracy vs. Precision)

ACCURACY and PRECISION are often confused. Accuracy relates to the correctness or truthfulness of a measurement or computation. Precision relates to the number of decimal places involved.

COMPUTATIONS can be extremely precise without being the least bit accurate (pi equal to 4.141592653), and conversely may be accurate witbout being especially precise (pi equal to 3.14). A value of pi such as 3.141592653 is both accurate and precise.

MEASUREMENTS, as opposed to computations, raise the distinction between the precision of the measuring device and that of the quantity being measured. In this case, precision is sometimes defined as "repeatability." A device capable of measuring temperature precisely may still not be useful if the temperature itself is not controlled precisely enough to allow for a repeatable measurement.

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