Homework 3

1.

What is a closed​ question? What is an open​ question? Discuss the advantages and disadvantages of each type of question.

What is a closed​ question? What is an open​ question?

1. A closed question is a​ free-response question, whereas an open question has fixed choices for answers.
2. A closed question has many correct​ answers, whereas an open question has only one correct answer.
3. A closed question has fixed choices for​ answers, whereas an open question is a​ free-response question.
4. A closed question always has yes or no​ answers, whereas an open question is a​ free-response question.

Discuss the advantages and disadvantages of each type of question.

1. Closed questions are easier to​ analyze, but limit the responses. Open questions allow respondents to state exactly how they​ feel, but are harder to analyze due to the variety of answers and possible misinterpretation of answers.
2. Closed questions allow respondents to state exactly how they​ feel, but are harder to analyze due to the variety of answers and possible misinterpretation of answers. Open questions are easier to​ analyze, but limit the responses.
3. Closed questions are easier to​ analyze, because they usually gather more accurate data. Open questions limit the​ responses, but are harder to analyze since not every viewpoint will be covered.
4. Closed questions are harder to​ analyze, because they limit the responses. Open questions allow respondents to state exactly how they​ feel, but are easier to analyze due to the variety of answers.

2 What does it mean when a part of the population is​ under-represented?

Choose the correct answer below.

1. A part of the population is​ under-represented when it is proportionally smaller in its population than in a sample.
2. A part of the population is​ under-represented when individuals selected to be in the sample who do not respond to the survey have different opinions from those who do.
3. A part of the population is​ under-represented when it is proportionally smaller in a sample than in its population.
4. A part of the population is​ under-represented when their answers on a survey tend not to reflect their true feelings.

3.  Match each word or phrase to its definition.

Drag each word or phrase given above into the appropriate definition below.

The techniques used to select individuals to be in the sample favor one part of the population over another.

The answers on a survey do not reflect the true feelings of the respondent.

The results of the sample are not representative of the population.

The individuals selected to be in the sample who do not respond to the survey have different opinions from those who do respond.

4. Distinguish between nonsampling error and sampling error.

Choose the correct answer below.

1. Nonsampling error is the error that results from​ undercoverage, nonresponse​ bias, response​ bias, or​ data-entry errors. Sampling error is the error that results because a sample is being used to estimate information about a population.
2. Nonsampling error is the error that results from the process of obtaining the data. Sampling error is the error that results from​ undercoverage, nonresponse​ bias, response​ bias, or​ data-entry errors.
3. Nonsampling error is the error that results because a sample is being used to estimate information about a population. Sampling error is the error that results from​ undercoverage, nonresponse​ bias, response​ bias, or​ data-entry errors.
4. Nonsampling error is the error that results from randomness. Sampling error is the error that results from using a sample to estimate information about a population.

5.  The owner of a shopping mall wishes to expand the number of shops available in the food court.  He has a market researcher survey the first 110 customers who come into the food court during weekday mornings to determine what types of food the shoppers would like to see added to the food court. Complete parts​ (a) and​ (b) below.

​(a) The survey has bias. Determine whether the flaw is due to the sampling method or the survey itself. For biased​ surveys, identify the cause of the error.

What is the cause of the​ bias?

1. Sampling bias
2. Response bias
3. Nonresponse

(b) Suggest a remedy to the problem.

Which of the following is the best way to remedy this​ problem?

1. Ask customers throughout the day on both weekdays and weekends.
2. Increase the sample size so that more people respond to the question.
3. Reword the question so that it is balanced.

6.  The survey has bias.​ (a) Determine the type of bias.​ (b) Suggest a remedy.  A pro-intelligent design advocate wants to estimate the percentage of people who favor teaching intelligent design in schools. She conducts a nationwide survey of 1140 randomly selected adults 18 years and older. The interviewer asks the​ respondents, ​”Do you favor offering alternative viewpoints by teaching intelligent design and evolution?​”

​

(a) Which of these best describes the bias in the​ survey?

1. Nonresponse bias
2. Undercoverage bias
3. Sampling bias
4. Response bias

​

(b) How can the bias be​ remedied?

1. The interviewer should survey people under 18 as well.
2. The interviewer should survey people by phone and in person.
3. The interviewer should survey a greater number of adults 18 and older.
4. The interviewer should reword the question.

7. The survey has bias.​ (a) Determine the type of bias.​ (b) Suggest a remedy.A polling organization conducts a study to estimate the percentage of households that have high-speed Internet access. It mails a questionnaire to 1788 randomly selected households across the country and asks the head of each household if he or she has high-speed Internet access. Of the 1788 households​ selected, 10 responded.

​(a) Which of these best describes the bias in the​ survey?

1. Nonresponse bias
2. Sampling bias
3. Response bias
4. Undercoverage bias

​(b) How can the bias be​ remedied?

1. The polling organization should try contacting households that do not respond by phone or​ face-to-face.
2. The polling organization should only select households in a single state.
3. The polling organization should mail the questionnaire to each person in the households.
4. The polling organization should mail the questionnaire to a greater number of households.

8. Surveys tend to suffer from low response rates. Based on past​ experience, a researcher determines that the typical response rate for an​ e-mail survey is 20​%. She wishes to obtain a sample of 200 ​respondents, so she​ e-mails the survey to 2000 randomly selected​ e-mail addresses. Assuming the response rate for her survey is 20​%, will the respondents form an unbiased​ sample? Explain.

Is the sample​ unbiased?

1. No. The survey was not given to the entire population.
2. No. The survey still suffers from undercoverage​ (sampling bias), nonresponse​ bias, and potentially response bias.
3. Yes. The number of respondents will be approximately 400​, that​ is, two times greater than the needed size of the sample.
4. Yes. The sample was a randomly selected group of​ e-mail addresses, which does not introduce bias.

9. Suppose a random phone survey is being conducted to find the population’s feelings on the new stamp design. If the randomly selected person is not home, they are called again later in the day.   What tactic is being used to increase the response rate for this​ survey?

Choose the correct answer below.

1. The company is using callbacks.
2. The company is using a reward.
3. The company is using a phone survey.
4. The company is selecting people randomly.

10.   Suppose that a magazine predicted that Candidate A would defeat Candidate B in a certain election. They conducted a poll of telephone directories with a response rate of 23​%.  On the basis of the​ results, the magazine predicted that Candidate A would win with​ 57% of the popular vote.​ However, Candidate B won the election with about​ 62% of the popular vote. At the time of this​ poll, most households with telephones belonged to the party of Candidate A. Name two biases that led to this incorrect prediction.

Choose the correct answer below.

1. Sampling​ bias: Using an incorrect frame led to undercoverage.Nonresponse​ bias: The low response rate caused bias.
2. Nonresponse​ bias: The low response rate caused bias. Response​ bias: The way the poll was administered showed bias.
3. Sampling​ bias: Using an incorrect frame led to undercoverage. Response​ bias: The way the poll was administered showed bias.

11.  Discuss a possible advantage of offering rewards or incentives to increase response rates. Are there any​ disadvantages?

Discuss a possible advantage.

1. A possible advantage of offering rewards or incentives to increase response rates is that if the sponsor of the survey has a vested interest in the​ results, then the rewards or incentives add credibility to the survey.
2. A possible advantage of offering rewards or incentives to increase response rates is that the monetary outlays the researchers need to make for the survey are lower.
3. A possible advantage of offering rewards or incentives to increase response rates is that respondents put more effort into completely and accurately answering the survey questions because they feel obligated.
4. A possible advantage of offering rewards or incentives to increase response rates is that the sample has a higher proportion of people that are interested in the reward or incentive than the population.

Determine if there are any disadvantages.

1. A possible disadvantage of offering rewards or incentives to increase response rates is that too many people selected for the sample respond to the survey.
2. A possible disadvantage of offering rewards or incentives to increase response rates is that the people interested in the rewards or incentives differ from the population in some way that is important to the​ study, causing biased results.
3. A possible disadvantage of offering rewards or incentives to increase response rates is that people who would not normally participate in the survey actually do participate in the survey.
4. There are no disadvantages of offering rewards or incentives to increase response rates.