A hospital employs 420 nurses, 180 doctors and 150 other clinical staff. A researcher wants a proportional stratified sample of 50 staff, selected randomly within each stratum.
Calculate the three allocations.
Explain one advantage over opportunity sampling in the hospital café.
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.