At its website, a polling company publishes results of a new survey each day. At the end of the survey, the following paragraph is printed summarizing how the results were collected.

Results are based on telephone interviews with 1,008 national adults, aged 18 and older, conducted on April 2-5, 2007 ... In addition to sampling error, question wording and practical difficulties in conducting surveys can introduce error or bias into the findings of public opinion polls.

Use this information to answer the following:

1. For this survey identify the population of interest.

• everyone in the nation that is 18+ years old
• everyone in the nation
• everyone that responded to the call
• everyone that was called, whether they responded or not

2. The company performs its surveys by phoning numbers generated at random from a computer program. What is the sampling frame?

• everyone that did not have their phone number generated
• everyone with a telephone
• everyone that responded to the call
• everyone that had their phone number generated

3. What problems, if any, would you be concerned about in matching the sampling frame with the population?

• Some people do not have telephones.
• Some people were not available to answer the call.
• Some people answered the call, but chose not to participate in the survey.