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. Compare tightly grouped readings with a shifted tight group. Show the known reference before judging accuracy.
Engineering and scientific investigation · Discover & try
What can repeated readings reveal?
Reading level 2 of 5 · DevelopingChange
Word help
Mean
The sum of readings divided by their number.
Spread
How far apart the readings lie.
Watch · Try · Explain
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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