Question 1

For a survey of American diets a random sample of 1000 people were contacted. Of the 1000 people, 340 people completed the questionnaire. The results of this study, if applied to all Americans, are questionable because of

Accepted Answer

A)  a large margin of error. 
B)  selection bias. 
C)  nonresponse bias. 
D)  response bias.

Question 2

Use the following information for questions:
 These questions pertain to how to collect a random sample of 800 airline passengers from 100 particular flights leaving San Francisco International Airport. Assume there are 200 passengers aboard each flight.
-Describe how to draw the sample as a stratified random sample, using the 100 flights as the strata.

Accepted Answer

The answer of Use the following information for questions:
 These...

Question 3

The biggest problem with open questions is that the results can be difficult to summarize. If closed-form questions are preferred, explain how a pilot survey might be used to better formulate the closed-form questions.

Accepted Answer

The answer of The biggest problem with open questions is...

Question 4

A company has 500 employees and would like to select a simple random sample of 25 of them for a study. Of the following, only one fits the definition of a simple random sample. Which one is it?

Accepted Answer

A)  Randomly choose one person whose last name begins with A, one with B, and so on, omitting X because it's least common. 
B)  Randomly choose 25 pages from the employee directory, then choose the first person listed on each of those pages. 
C)  Number the employees from 1 to 500 based on seniority and randomly choose one person from the first 20 names on the list, one from the next 20, and so on. 
D)  Number the employees from 1 to 500 in random order and choose the first 25 names on the list.

Question 5

Use the following information for questions:
 A poll is planned to determine what proportion of all students favor an increase in fees to support a new track and field stadium. For each study design, identify the main problem.
-The questionnaire will be published in the student newspaper and the first 1000 completed questionnaires will be analyzed.

Accepted Answer

A)  Wrong sampling frame 
B)  Volunteer response 
C)  Response bias 
D)  Nonresponse bias

Question 6

A professor wanted to find out whether students enrolled in her statistics class would like her to increase her office hours. She plans to take a random sample of 20 students among those coming to class on the next lecture day. Explain what the difficulty with her method is.

Accepted Answer

The answer of A professor wanted to find out whether...

Question 7

A random sample of Americans at least 65 years old showed that 32% believe their health is extremely important. If the sample size was 100, approximately what was the margin of error?

Accepted Answer

A)  1% 
B)  5% 
C)  10% 
D)  15%

Question 8

A weight-loss company is trying to promote its product. Based on a sample of 10 of their clients they model the relationship between starting weight and weight after 4 weeks using their product. It turns out that these 10 clients were selected because they had lost a decent amount of weight in 4 weeks. Clients who had lost hardly any weight or even gained weight were not included for this study. The results of this study, if applied to all clients, are questionable because of

Accepted Answer

A)  lack of accuracy. 
B)  selection bias. 
C)  nonresponse bias. 
D)  response bias.

Question 9

A survey is planned to be done by contacting a random sample of people who have bought something over the Internet; the question would ask whether sales made over the Internet should be taxed or not. The purpose is to estimate the proportion of all Americans who would support an Internet sales tax. Explain why selection bias would be a problem for this survey.

Accepted Answer

The answer of A survey is planned to be done...

Question 10

A magazine printed a survey in its monthly issue and asked readers to fill it out and send it in. Over 1000 readers did so. This type of sample is called a

Accepted Answer

A)  cluster sample. 
B)  stratified sample. 
C)  simple random sample. 
D)  self-selected sample.

Question 11

A census differs from a sample survey because

Accepted Answer

A)  a sample survey is only done when measuring the units will destroy them. 
B)  a census is only done when measuring the units will destroy them. 
C)  in a sample survey the whole population is measured. 
D)  in a census the whole population is measured.

Question 12

A student organization is trying to decide whether or not to offer more movies on campus. A random sample of students is about to be asked if they are in favor of more free movies on campus. What sample size would be needed to provide a margin of error of about 3%?

Accepted Answer

A)  n = 33 
B)  n = 1000 
C)  n = 1001 
D)  n = 1112

Question 13

Sometimes questions are worded in such a way that the meaning is misinterpreted by a large percentage of the respondents. Which of the following types of bias would be most likely to be produced?

Accepted Answer

A)  Nonresponse bias 
B)  Response bias 
C)  Intentional bias 
D)  Unintentional bias

Question 14

Use the following information for questions:
 A poll is planned to determine what proportion of all students favor an increase in fees to support a new track and field stadium. For each study design, identify the main problem.
-A random sample of students will be called on the phone on Friday night and asked whether they favor a fee increase.

Accepted Answer

A)  Wrong sampling frame 
B)  Volunteer response 
C)  Response bias 
D)  Nonresponse bias

Question 15

A Gallup poll reported that 88% of Americans say they have health insurance. If the sample size was 2500, an approximate 95% confidence interval for the proportion of all Americans who say they are insured is

Accepted Answer

A)  between 80% and 96%. 
B)  between 84% and 92%. 
C)  between 86% and 90%. 
D)  between 87.3% and 88.7%.

Question 16

In the College of Engineering exams aren't proctored. Students are required to write out the University honor code. They sign their name to pledge that they didn't cheat. But the engineering professors cannot observe if students cheat or not. One way to collect data on this topic would be to use an "exit poll": Have a Graduate Student Instructor ask the students if they cheated on the exam after the student has left the exam room. The results of this study, if applied to all students in the College of Engineering, are questionable because of

Accepted Answer

A)  lack of accuracy. 
B)  selection bias. 
C)  nonresponse bias. 
D)  response bias.

Question 17

Use the following information for questions:
 The next  question are based on the following row of digits from a random number table. Use these digits to select a random sample following steps 1 through 4 in the text.
00157$\quad$ 37071 $\quad$ 79553 $\quad$ 31062$\quad$ 42411$\quad$ 79371 $\quad$25506$\quad$ 69135
-Suppose that a group of 10 students are numbered from 0 to 9. Draw a simple random sample of 5 students by starting with the digit 1 in the first string of digits 00157. Which 5 students would be selected?

Accepted Answer

The answer of Use the following information for questions:
 The...

Question 18

Which of the following would be most likely to produce response bias in a survey?

Accepted Answer

A)  Using questions with biased wording. 
B)  Only receiving responses from half of the people in the sample. 
C)  Conducting interviews by telephone instead of in person. 
D)  Using a random sample of students at a university to estimate the proportion of people who think the legal drinking age should be lowered.

Question 19

A Gallup poll reported that 58% of Americans say they are satisfied with the costs of healthcare. If the margin of error was 5%, approximately what was the sample size?

Accepted Answer

A)  10 
B)  200 
C)  400 
D)  1600

Question 20

Use the following information for questions:
 Olivia wants to learn a foreign language. To get an idea of how satisfied other students were after taking a foreign language course, she decides to take a random sample of 20 students.
-If Olivia randomly selects 5 students from French, 5 from German, 5 from Spanish, and 5 from Chinese, the sampling method is a

Accepted Answer

A)  simple random sample. 
B)  stratified random sample. 
C)  cluster sample. 
D)  systematic sample.

Exam 5: Sampling: Surveys and How to Ask Questions