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Accuracy and Precision

Accuracy and Precision

Author: Sarah Kummeth

Learn what accuracy, precision, systematic error and random error are.
Figure out how to determine if data is accurate, precise, both or neither.
Understand how systematic and random errors impact accuracy and precision.

Use an example experiment to identify accuracy, precision, systematic error and random error.

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New Vocabulary to Remember

Accuracy- the extent to which a given measurement agrees with the true value.

Precision- the extent to which a given set of measurements of the same sample agree with their mean.

Systematic Error- A persistent error that cannot be attributed to chance, but to inaccuracy in the statistical system or in the  measurement instrument used.

Random Error- A measurement mistake caused by factors that vary from one measurement to another. Error due to chance.


For Example, an Experiment

Random and Systematic Errors

Random Error and Systematic Error impact accuracy

and precision by scattering results or shifting the

results' measures.

Some examples of Random Error are:

  • -Wind or any other environmental change which cannot be stopped (temperature change, rain, etc.)
  • -Spilling or any other human error.

Some examples of Systematic Error are:

  • -Zero-ing out a scale with an item on it (or starting anything at a non-real zero- like the end of a ruler instead of the 0 marking)
  • -Un-even scale for measurement

Identify the Systematic and Random Errors