Histogram reconstruction
Objective. Recover frequencies from density and class width.
- 1. Learn
- 2. Worked example
- 3. Practice
- 4. Feedback
- 5. Continue
Learn: the key idea
Histogram reconstruction is developed here as connected GCSE mathematics, not a memorised shortcut. Estimate, compare and critique evidence from grouped and sampled data. The lesson moves from a precise representation and key definitions to fluent procedure, linked reasoning and an unfamiliar application. Learners compare possible methods, state restrictions and assumptions, preserve exact values where appropriate, and justify accuracy, notation and units before evaluating whether the result is mathematically and contextually reasonable.
Worked example
Which measure is most resistant to outliers?
- 1Translate the information into a labelled diagram, table, graph or algebraic statement and identify every constraint.
- 2Select the most efficient GCSE method, explain why its conditions apply, and keep exact values until approximation is requested.
- 3Carry out each transformation on a separate justified line, tracking signs, units, domains and required accuracy.
- 4Verify with substitution, an inverse method, estimation or a second representation. The checked result is median.
Answer: median
Concept mastery
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Practice
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Start practisingCommon mistake. A common error in histogram reconstruction is applying a familiar rule before checking its conditions, domain or direction. Name the structure first, retain exact values, and test the final result against every original constraint.
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