Identify the sampling techniquesused, and discuss potential sources of bias(if any). Explain.

In1965, researchers used random digit dialing to call 800 people and ask what obstacles kept them from eatinghealthier.

What type of sampling wasused?

A.

Cluster sampling wasused, since the phone numbers were divided intogroups, several groups wereselected, and each number in those groups was called.

B.

Systematic sampling wasused, since phone numbers were selected from a list using a fixed interval between phone numbers.

C.

Convenience sampling wasused, since the 800 phone numbers that were easiest to reach were selected.

D.

Simple random sampling wasused, since each number had an equal chance of beingdialed, so all samples of 800 phone numbers had an equal chance of being selected.

What potential sources of bias werepresent, ifany? Select all that apply.

A.

Individuals may have not been available when the researchers were calling. Those individuals that were available may have not been representative of the population.

B.

Individuals may have refused to participate in the sample. This may have made the sample less representative of the population.

C.

No one talks honestly about their eatinghabits with people they do not know because it is too personal a subject. This may have led to untrue responses to the survey question.

D.

Telephone sampling only includes people who had telephones. People who owned telephones may have been older or wealthier onaverage, and may not have been representative of the entire population.

E.

There were no potential sources of bias.