Question

A newspaper hires a polling company to determine the level of support in the county for raising property taxes in order to increase funding for local schools. The polling company calls phone numbers chosen at random from a phone number registry between the hours of 5 p.m. and 7 p.m. What are some potential sources of bias in this sampling method?

Answer 1

There are three correct answers:

Explanation:

The method excludes people who have unregistered numbers.

The method excludes people who work between​ 5:00 P.M. and​ 7:00 P.M.

The method excludes people who do not have phones.

Answer 2

Some sources of bias may be:

1. The fact the company is calling in such a narrow time window. They need to expand their hours of operation.
2. Not everyone has a listed phone number, and many cell phones are unlisted, so that leaves many people out of the picture. The sample is likely not representative of the population. The company may be better off doing email or social media surveying methods.
3. Many people often get annoyed at unsolicited phone calls, so they may not be willing to do a survey.
4. Those that do answer the survey may show off volunteer response bias which is often present in political surveys.