A-level · Statistical sampling

Populations, samples and the large data setExam-style questions

What a population, a census and a sample actually are; the sampling units and the sampling frame; why you would sample rather than take a census (and when a census is impossible); and how a sample can be unrepresentative — including the trap of combining overlapping samples.

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7 questions · A-level level · mark scheme and worked solution on each · no sign-up to try

DifficultyAllLevel 2Level 3
  1. 1
    Explain the difference between a population and a sample.
    Level 2 · 2 marksTry it
  2. 2
    State one advantage and one disadvantage of taking a census rather than a sample.
    Level 2 · 2 marksTry it
  3. 3
    In the context of sampling, explain what is meant by
    (a) a sampling unit, and (b) a sampling frame.
    Level 3 · 2 marksTry it
  4. 4
    A factory tests the lifetime of its light bulbs by running each one until it fails. Explain why a sample, rather than a census, must be used.
    Level 3 · 1 markTry it
  5. 5
    A researcher wants to know the average height of 1616-year-olds in a city. Identify the population and a suitable sampling unit.
    Level 3 · 2 marksTry it

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