Repeated measurements show how much readings vary. A tight group can be very repeatable yet still miss a known reference. Compare both the spread and the group’s position relative to that reference. More readings do not automatically remove a consistent error. Short-term variation, instrument resolution and changes in conditions can all influence measured results. Repeated observations help estimate variation, while reference checks can expose persistent offsets. Averaging more values does not automatically remove systematic error. Our small invented sets illustrate these distinctions rather than establish a statistical confidence interval for a real measurement.
Engineering and scientific investigation · Discover & try
What can repeated readings reveal?
Reading level 4 of 5 · FluentChange
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Mean
The sum of readings divided by their number.
Spread
How far apart the readings lie.
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See how it works
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Invented readings with a displayed mean, range and optional reference. These summaries reveal different features of a measurement process.
What to look for
- The readings cluster around the known50 mm reference.
- They agree with one another but cluster around55 mm, away from the reference.
- Repeated readings expose variation that a single reading hides.
Explain what you noticed
A different virtual balance repeats readings that are all 3 g above a reference. What should be investigated?
Keep this idea: Agreement between repeated readings is different from agreement with a reference.
Follow the sources
- NIST/SEMATECH Engineering Statistics Handbook — Variability
- NIST/SEMATECH Engineering Statistics Handbook — Data Collection
Source material checked 2026-10-29. Explanations and activities by Nepedia. Source links do not imply endorsement.
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