Edexcel International A Level Physics

Revision Notes

6.13 Anomalous Readings

Test Yourself

Anomalous Readings

  • Experimental errors (also known as operator errors or ‘one off’ errors) will affect the results of an experiment and can produce anomalies
    • These anomalies should be identified during the evaluation of results and before drawing conclusions

  • Anomalies can be identified by looking for results or data points on a graph that do not fit with the trend or with other repeat readings carried out during the experiment
    • These anomalous results will show a larger difference from the mean than the rest of the results (a result is often taken to be anomalous if it differs from the mean result by more than 10%)
  • The results or ‘data’ collected from an experiment can be made more reliable if the experiment is repeated several times and anomalies are removed
    • This, in turn, allows more valid conclusions to be drawn

  • Anomalous results are always inconsistent with other readings e.g., a point that is not on the line of best fit of a graph

Identify-anomalies-on-graphs, IGCSE & GCSE Chemistry revision notes

Identifying an anomalous result from a graph

  • If an anomaly occurs in the experiment:
    • Ignore this value when calculating the mean
    • Repeat this measurement

Worked example

A student achieves a set of repeat readings for the current through a bulb.

2.5 mA 2.8 mA 6.1 mA 2.0 mA 2.3 mA

Calculate the mean current through the bulb.

1. Identify the anomalous result

    • The only result that doesn't fit with the rest of the data is 6.1 mA
    • This can be ignored when calculating the mean

2. Calculate the mean current

Mean current = fraction numerator 2.5 space plus space 2.8 space plus space 2.0 space plus thin space 2.3 over denominator 4 end fraction  = 2.4 mA

Exam Tip

When calculating the mean of some repeat readings for data given in your practical paper, always ignore any anomalous readings that are inconsistent when calculating the mean.

You've read 0 of your 0 free revision notes

Get unlimited access

to absolutely everything:

  • Downloadable PDFs
  • Unlimited Revision Notes
  • Topic Questions
  • Past Papers
  • Model Answers
  • Videos (Maths and Science)

Join the 80,663 Students that ❤️ Save My Exams

the (exam) results speak for themselves:

Did this page help you?

Katie M

Author: Katie M

Katie has always been passionate about the sciences, and completed a degree in Astrophysics at Sheffield University. She decided that she wanted to inspire other young people, so moved to Bristol to complete a PGCE in Secondary Science. She particularly loves creating fun and absorbing materials to help students achieve their exam potential.