A researcher randomly selects four tutor groups and surveys every student in those groups, obtaining 82 responses.
Name the broad sampling structure used.
Explain why this is not a simple random sample of 82 individual students.
Give one way the selected groups could make the result unrepresentative.
36 exam-style questions on OCR (MEI) A Level Maths 2.1 Sampling, covering 2.1.1 Population and sample, 2.1.2 Samples to make informal inferences, 2.1.3 Random sampling, 2.1.4 Variety of sampling techniques, 2.1.5 Select or evaluate sampling techniques, and 2.1 Sampling. Each one has a worked solution and a mark scheme showing where the marks go.