L3_Accuracy and Precision

Accuracy and Precision

  • Accuracy

    • Definition: The closeness of a measurement to the true or accepted value.
    • Related Concept: Accepted Value
    • Definition: The value that all scientists in the field have agreed upon and is considered a scientific fact.

  • Precision

    • Definition: Describes the closeness of multiple measurements, or its reproducibility.

Percent Error

  • Purpose: To determine the percent error of a measurement or lab result, which provides insight into the validity of the results.

  • Formula:

    • Percent Error = (measured value−accepted value)accepted value×100\frac{(\text{measured value} - \text{accepted value})}{\text{accepted value}} \times 100

  • Measured Value: The value gathered from the experiment.

  • Common Threshold: Results with a 5% margin are typically considered accurate.

Experimental Quality Indications

  • High Accuracy:

    • Description: The experimental procedure aligns with existing scientific data and leads to the correct answer.

  • High Precision:

    • Description: The experiment was conducted well with consistent methods throughout.

  • Summary of Accuracy and Precision Combinations:

    • Low Accuracy & Low Precision
    • High Accuracy & Low Precision
    • Low Accuracy & High Precision
    • High Accuracy & High Precision

  • Importance: Understanding accuracy and precision is essential to evaluate how well an experiment was conducted and how reliable the results are.