What is Accuracy: Definition and 234 Discussions

In a set of measurements, accuracy is closeness of the measurements to a specific value, while precision is the closeness of the measurements to each other.
Accuracy has two definitions:

More commonly, it is a description of systematic errors, a measure of statistical bias; low accuracy causes a difference between a result and a "true" value. ISO calls this trueness.
Alternatively, ISO defines accuracy as describing a combination of both types of observational error above (random and systematic), so high accuracy requires both high precision and high trueness.Precision is a description of random errors, a measure of statistical variability.
In simpler terms, given a set of data points from repeated measurements of the same quantity, the set can be said to be accurate if their average is close to the true value of the quantity being measured, while the set can be said to be precise if the values are close to each other. In the first, more common definition of "accuracy" above, the two concepts are independent of each other, so a particular set of data can be said to be either accurate, or precise, or both, or neither.

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  1. P

    Measuring Pi/6 for Peak Height Accuracy: +_20 or +_10 m

    Homework Statement A hiker is at the base of a mountain and can get the horizantal distance between himself and the peak through GPS device:750 m. And suppose we know the actual measurements: It's a right triangle with an opposite= 750 tan (pi/6) = 433 m , an adjacent= 750 m, and a...
  2. G

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  3. C

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  4. russ_watters

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  5. M

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  6. M

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  7. M

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  8. N

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  9. C

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  10. F

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  11. A

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  12. B

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  13. W

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  14. N

    Amount of Terms Required to Find a Sum at an Indicated Accuracy

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  15. I

    Load Cell Accuracy | Capacity >200Kg | 10g or Better Accuracy

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  16. U

    Calculating the Relative Error & Improving Accuracy of Measurements

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  17. Pengwuino

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  18. G

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  19. D

    Required Precision for GPS Distance Measurement

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  20. Q

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  21. S

    Which Type of Sensor is More Accurate: Thermocouple or RTD?

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  22. T

    Absolute Zero and Absolute Accuracy

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  23. R

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  24. Averagesupernova

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  25. K

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  26. B

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  27. G

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  29. L

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  30. L

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  31. F

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  32. cepheid

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  33. I

    What is the most accurate method for measuring 6 mL of water?

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  34. G

    Accuracy, Fibonacci + Golden Ratio

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  35. N

    Accuracy of Numerical Integration Methods

    Hi, does anyone know what sort of methods I could use to test the accuracy of the numerical solution of the integral equation? Many thanks
  36. M

    Accuracy of Current and Voltage Measurements

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  37. S

    Accuracy of Gravity: -9.8m/s/s +- _______m/s/s

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  38. G

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  39. C

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  40. W

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  41. D

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  42. wolram

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  43. M

    Measuring Accuracy: Quantitative or Qualitative?

    What is the difference between accuracy of a measurement and its level of accuracy? Is the level of accuracy quantitative or a qualitative measure?
  44. U

    Examining the Accuracy of "Moon's Orbit Around Earth"

    hey, can somebody please help me examine the truth of the statement "the moon moves in a near-circular orbit around earth. because the Earth is so much more massive, it own motion is not appreciably affected by the moons presence" ?
  45. U

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  46. J

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  47. I

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    If an electromechanical instrument's (say a galvanometer) accuracy is given as a percentage of its full scale deflection, what would its accuracy be at anything lower than full scale deflection? My thoughts: If say full scale deflection is 100V The error is +-1% which is +-1V, Does that...
  48. brewnog

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  49. D

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  50. B

    How Can I Calculate Sample Accuracy for a Web Poll?

    Ok. I'm fairly new so go easy on me. I apologise if this is posted in the wrong section. Can someone point me in the right direction of being able to work out samples of a web poll. A web poll I did returned the following results for a sample of 40 people and spending habits of a...
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