Chapter 12, Problem 27E

(a)

To determine

To explain why is it difficult to use a simple random sample here.

Explanation of Solution

It is given in the question that anytime a survey is conducted then we must take care to avoid under-coverage. Thus, it is difficult to use a simple random sample here because not everyone has an equal chance of being selected. People with unlisted numbers, people without phones, or those at work cannot be reached.

(b)

To determine

To describe a more convenient but still random, sampling strategy.

Explanation of Solution

It is given in the question that anytime a survey is conducted then we must take care to avoid under-coverage. So, they planned to select names from the city notebook and call their homes. Thus, a more convenient but still random, sampling strategy will be to generate random numbers and call at random times.

(c)

To determine

To explain what kind of households are likely to be included in the eventual sample of opinion and excluded also.

Explanation of Solution

It is given in the question that anytime a survey is conducted then we must take care to avoid under-coverage. So, they planned to select names from the city notebook and call their homes. Thus, we can say that the kind of households are likely to be included or excluded in the eventual sample of opinion will be that under the original plan, families in which one person stays home are more likely to be included. Under the second plan, many more are included. People without phones are still excluded.

(d)

To determine

To explain how does it improve the sampling design.

Explanation of Solution

It is given in the question that anytime a survey is conducted then we must take care to avoid under-coverage. So, they planned to select names from the city notebook and call their homes. Thus, it will then improve the sampling design as it improves the chance of selected households being included.

(e)

To determine

To explain how would this improve our design and find out is anyone still excluded.

Answer to Problem 27E

People with phones are still excluded.

Explanation of Solution

It is given in the question that anytime a survey is conducted then we must take care to avoid under-coverage. So, they planned to select names from the city notebook and call their homes. Thus, this would improve our design because this takes care of phone numbers. Time of day may be an issue. People with phones are still excluded in the survey conducted.