A-level · Statistical sampling

Random sampling — simple, systematic and stratifiedExam-style questions

The three sampling methods that use chance: simple random sampling (every sample equally likely), systematic sampling (every kth unit after a random start), and stratified sampling (proportional allocation across groups), with how to carry each out and the advantages and drawbacks that examiners ask for.

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

DifficultyAll Level 2 Level 3

1
A systematic sample of $50$ is to be taken from a population of $800$ people, listed in order.
(a) Find the sampling interval.
(b) Describe how the first member is chosen.
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2
A school has $1200$ students, of whom $480$ are in Year $12$ . A stratified sample of $60$ students is taken. Find how many should be from Year $12$ .
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3
A company has $300$ employees: $150$ men, $90$ women in the office and $60$ in the warehouse. A stratified sample of $40$ is required. Find how many should be taken from each group.
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4
A systematic sample of $80$ is taken from $2000$ items on a production line. Find the sampling interval.
Level 3 · 1 markTry it
5
Give one advantage of stratified sampling over simple random sampling.
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