A factory list contains 1440 employees arranged in a repeating pattern of 12 job roles. A systematic sample of 120 uses interval 12.
Explain why this sample may be seriously biased.
Describe a simple random alternative.
State one practical advantage the systematic sample would otherwise have.
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.