Mathematical Methods · Unit 4 · Sampling and proportions · Random sampling
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A market researcher wishes to gather information about customer preferences from a large shopping centre. The researcher stands at the main entrance during lunch hours and interviews every 15th person who walks past. Which feature of this sampling method violates the criteria for a random sample?
A university researcher is investigating student study habits. She assigns each of the 2400 students in the Faculty of Science a unique number from 1 to 2400, then uses a random number generator to select 80 students for her sample. (a) State the sampling method being used. (1 mark) (b) Calculate the probability that any particular student is selected in this sample. Express your answer as a percentage correct to two decimal places. (2 marks)
A marine biologist is studying fish populations in a coastal reserve. The reserve contains 850 tagged fish. To conduct a health survey, the biologist uses a random number generator to select 60 fish by their tag numbers. Explain why this sampling method produces a random sample, and calculate the probability that any individual tagged fish in the reserve is selected for the survey. Express your answer as a simplified fraction.