One of 12 wards, A to L, is to be selected for an inspection. A computer generates a two-digit random integer from 00 to 99, with every integer equally likely. The officer assigns eight integers to each of A to K and assigns the remaining twelve integers to L.
Show that this method does not give every ward the same probability of selection.
Describe a corrected method using the same generator that gives every ward the same probability of selection.
Find the probability that a specified ward is eventually selected using your corrected method.
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.