4.04 Summary
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Random errors cause measurement values to vary randomly from the true value. They are caused by random variations in measurement technique and environmental factors.
- Statistics can be used to reduce random errors using a set of repeated measurements
- Techniques exist which can:
- be used to determine when an adequate number of repeated measurements have been made
- produce a nominal value which is closer to the true value
- determine a suitable uncertainty interval to complete the new measurment value
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On introductory courses it is not uncommon for students to be allowed to
- assume that about 10 repeated measurments will be adequate
- take the average of these values as the nominal value
- take the uncertainty to be the same as the individual measurement
- Systematic errors cause a consistent offset between the measurement value and the true vaue
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Systematic errors are caused either by consistent mistakes in the measuring technique or calibration errors in the measuring equipment used (calibration errors will be discussed in detail in the next section)
