Question

The list of individuals from which a sample is actually selected is called the sampling frame. Ideally, the sampling frame should list every individual in the population, but in practice this is often difficult. A sampling frame that leaves out part of the population is a common source of undercoverage. In the following questions select all choices that apply; to receive credit for the question you must select all the correct choices and only the correct choices.

Question 1. A pollster wants to select a random sample of households in a particular community. The pollster randomly selects a sample of households in the community from the community telephone directory available in the public library. What households are omitted from this sampling frame?

1Households that connect to the internet with their phone line.

2Households that possess only cellphones Households with a second line for the fax machine.

3Households that have moved into the community since the most recent community telephone directory was printed.

4Households with unlisted numbers. Households with more than one line. Poor households (cannot afford a phone)

5Households without telephones.

Question 2. What types of people do you think are most likely to live in the omitted households selected in question 1?

1These people will probably be underrepresented in the sample. lower income people (cannot afford a phone)

2people who choose not to list their numbers people who choose not to have phones

3people who graduated from UNC-Chapel Hill

4jobless people who have moved into the community to look for employment since the most recent community telephone directory was printed

5people who drive hybrid automobiles high income people

Question 3. It is usual in telephone surveys to use random dialing equipment that selects the last four digits of a telephone number at random after being given the land-line exchange (the first three digits; note that cell phone exchanges differ from land-line exchanges). Which of the households you selected in Question 1 above will be included in this sampling frame by random digit dialing?

1Households that possess only cellphones Poor households (cannot afford a phone)

2Households with unlisted numbers

3Households without telephones

4Households with land-line telephones that have moved into the community since the most recent community telephone directory was printed.

Answer 1

Question 1. A pollster wants to select a random sample of households in a particular community. The pollster randomly selects a sample of households in the community from the community telephone directory available in the public library. What households are omitted from this sampling frame?

The correct options are all households are omitted which cannot be contacted with community telephone directory. We assume here that cellphones are not listed in the community telephone directory. The correct options are -

2Households that possess only cellphones Households with a second line for the fax machine.

3Households that have moved into the community since the most recent community telephone directory was printed.

4Households with unlisted numbers. Households with more than one line. Poor households (cannot afford a phone)

5Households without telephones.

Question 2. What types of people do you think are most likely to live in the omitted households selected in question 1?

The correct options are -

1These people will probably be underrepresented in the sample. lower income people (cannot afford a phone)

2people who choose not to list their numbers people who choose not to have phones

4jobless people who have moved into the community to look for employment since the most recent community telephone directory was printed

Question 3. It is usual in telephone surveys to use random dialing equipment that selects the last four digits of a telephone number at random after being given the land-line exchange (the first three digits; note that cell phone exchanges differ from land-line exchanges). Which of the households you selected in Question 1 above will be included in this sampling frame by random digit dialing?

The households with land-line telephones can be contacted with random digit dialing. The correct options are -

2Households with unlisted numbers

4Households with land-line telephones that have moved into the community since the most recent community telephone directory was printed.