Question

Identify the type of bias and give an explanation to why this scenario is biased. (3 marks each, 1 mark for the correct bias, 2 marks for the explanation). a) A survey uses a cluster sample of Toronto residents to determine public opinion on whether the provincial government should increase funding for the public transit. b) Every fourth person entering a public library is asked : Do you think Ian Williams should receive the Giller prize for his brilliant and critically acclaimed new novel ?

Answer 1

a)

This is a case of selection bias. We are just selecting a single kind of population i.e Toronto population as a sample. The population should be chosen randomly here and not the way it is chosen.

In this case, different opinions won't be captured, which makes it a biased survey.

b)

Every fourth person is asked, here we do not know if the person asked follows Ian Williams or Giller prize. If that is the case, then the persona asked, can reply anything, without knowing it. It is a case of response bias.

Persons participating in the survey should have some knowledge or opinion on that topic.