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Accuracy and precision

  1. Oct 10, 2005 #1
    What is the difference between accuracy and precision?
  2. jcsd
  3. Oct 10, 2005 #2
    Hmm, I usually see this as

    *"Accuracy"-->how "close" your data/measurement/result is to an exact (more or less) value

    *"Precision"-->how "close" your data/measurements/results are to each other. Think of this as a measure of statistical spread and deviation from the mean of your particular data.

    E.g., let's say you want to hit a dart-board. You have some darts and you aim at the direct center.

    1) Accurate shooting ---> your darts are very close to the center

    2) Precise shooting ---> your darts are very close to each other

    It is possible to have (low accuracy, high precision), (high accuracy, low precision), (high accuracy, high precision), (low accuracy, low precision).
    Last edited: Oct 10, 2005
  4. Oct 10, 2005 #3

    Claude Bile

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    Science Advisor

    Taken from http://dictionary.reference.com/

    Accuracy -

    1. Conformity to fact.
    2. Precision; exactness.
    3. The ability of a measurement to match the actual value of the quantity being measured.

    Precision -

    1. The state or quality of being precise; exactness.
    2a. The ability of a measurement to be consistently reproduced.
    2b. The number of significant digits to which a value has been reliably measured.

  5. Oct 10, 2005 #4
    It's always the very last defintion ... :rolleyes:
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