A gym wants to investigate its members' opinions about opening times. A researcher uses the membership database and asks the first 30 members who enter after 9 am on a Monday.
Identify a suitable sampling frame.
Identify the sampling units.
State the sampling technique actually used.
Give one advantage and one disadvantage of this technique in this context.
36 exam-style questions on OCR A Level Maths 2.1 Statistical Sampling, covering 2.1.1 Population and sample, 2.1.2 Informal inferences from samples, 2.1.3 Sampling techniques, 2.1.4 Selecting or critiquing sampling techniques, and 2.1 Statistical Sampling. Each one has a worked solution and a mark scheme showing where the marks go.