Two simple random samples of 40 students are taken from the same college. In the first sample, 18 students prefer online textbooks. In the second sample, 29 students prefer online textbooks.
Calculate the sample proportions that prefer online textbooks.
Explain why the two proportions are different even though both samples were selected correctly.
A student claims that at least 70% of all students at the college prefer online textbooks. Comment on this claim.
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.