The collection of data

Which one of the following is continuous data?

Give one advantage and one disadvantage of using secondary data.

A school has the following numbers of students (data are illustrative, written for this paper): Year 7: 180 | Year 8: 200 | Year 9: 170 | Year 10: 150 | Year 11: 100. A stratified sample of 80 students is taken. Calculate how many students from Year 9 should be in the sample.

Ecologists catch and tag 40 fish in a lake. A week later they catch 50 fish, of which 8 are tagged. Use the Petersen capture–recapture method to estimate the population.

State one assumption made in using this method.

A survey contains the question: 'Don't you agree that the canteen food is too expensive?' Give two criticisms of this question.

Write an improved question with response boxes.

State one reason for carrying out a pilot study.

A student wants to investigate whether people in towns use public transport more than people in villages. Describe how they could plan and carry out this investigation.

Which sampling method selects the first people the researcher meets?

Explain the difference between a population and a sample.

Describe how to take a systematic sample of 50 from a list of 1,000 customers.

Explain what is meant by an extraneous variable, using an example from an experiment on plant growth.

Ecologists catch and tag 60 newts in a lake. A week later they catch 45 newts, of which 9 are tagged. Use the Petersen capture–recapture method to estimate the population.

State one assumption made in using this method.

Raw data from a survey of students' ages and hours of sleep (data are illustrative, written for this paper): (15, 8), (16, 7.5), (14, 9), (61, 7), (15, 28), (16, 8.5). Identify two values that should be checked or removed when cleaning the data, giving reasons.