Marcus wants to estimate the mean CO emission of the cars registered in his town. He stands outside a supermarket on a weekday morning and records the CO emission of the first 40 cars that park there.
Give one advantage of the method Marcus has used.
Give one reason why Marcus's sample may not be representative of the cars registered in his town.
28 exam-style questions on AQA A Level Maths 2.1 K: Statistical sampling, covering 2.1.1 Populations, samples and sampling techniques. Each one has a worked solution and a mark scheme showing where the marks go.