Prior to the mayoral election discussed in Exercise 27, the local newspaper conducted a poll. The paper surveyed a random sample of registered voters stratified by political party, age, sex, and area of residence. This poll predicted that Amabo would win the election with 52% of the vote. The newspaper was wrong: Amabo lost, getting only 46% of the vote. Do you think the newspaper’s faulty prediction is more likely to be a result of bias or sampling error? Explain.

Exercise 27:

Hoping to learn what issues may resonate with voters in the coming election, the campaign director for a mayoral candidate selects one block from each of the city’s election districts. Staff members go there and interview all the residents they can find.

For the following reports about statistical studies, identify the following items (if possible). If you can’t tell, then say so—this often happens when we read about a survey.

a) The population

b) The population parameter of interest

c) The sampling frame

d) The sample

e) The sampling method, including whether or not randomization was employed

f) Any potential sources of bias you can detect and any problems you see in generalizing to the population of interest