Exam 5: Sampling: Surveys and How to Ask Questions

A college department wants to learn about the jobs that its alumni are working in. An online survey is set up on the department website which invites alumni to complete and includes demographic questions and questions about their job (current and history). Give a problem that can arise with this survey.

A random sample of Americans showed that 4% believe their health care is excellent. If the conservative margin of error was 12.5%, what was the sample size?

What is the correct definition for an anonymous survey?

Which of the following is not an advantage of a sample survey over a census?

Use the following information for questions: According to a survey conducted by the Association for Dressings and Sauces (this is an actual association!), 85% of American adults eat salad at least once a week, so that 15% of American adults eat no salad at all! A nutritionist suspects that the percentage (of no-salad eaters) is wrong. She conducts a survey among a sample of adults in her area to test this idea. -What sample size would be needed to provide a margin of error no larger than 2%?

Use the following information for questions: The next question are based on a survey of 500 students living in campus dormitories. Questionnaires were mailed to each of the 500 students. The questionnaire asked if they had ever stolen a bicycle or not. The sample proportion who said they had stolen a bicycle was used to estimate the proportion of all students on campus who had ever stolen a bicycle. -Describe why selection bias is a problem for this survey.

A randomly selected sample of 1,000 college students was asked whether they had ever used the drug Ecstasy. Sixteen percent (16% or 0.16) of the 1,000 students surveyed said they had. Which one of the following statements about the number, 0.16 is correct?

A questionnaire on a table at a shopping mall was completed by 100 shoppers. The results were used to claim that the average amount of money spent by Americans increased from the previous year. Explain why this claim is questionable.

Which one of the following statements is true?

A recent poll reported that 62% of all college students believe there is extraterrestrial life. The 95% margin of error for the poll was 4%. Which of the following statements is correct?

Use the following information for questions: A claim was made that at a local college only 5% of the students that take the introductory statistics course will continue their education in statistics. The Statistics Department at the college believes that this value is too low and decides to conduct a sample survey of 100 students that completed the introductory course the previous term. -Identify the population.

A polling agency conducted a survey of 100 doctors on the question: "Are you willing to treat women patients with the recently approved pill RU-486?" The conservative margin of error associated with the 95% confidence interval for the percent who say 'yes' is

A researcher is conducting a survey among students to determine their mean age. Data is collected by asking the age of a simple random sample of 150 students. The researcher simply asked the ages of these students. The results of this study, if applied to all students in the university, are questionable because of

Use the following information for questions: A population under study is divided into 10 smaller groups (e.g. lab sections for a large class). The opinions of the people within each group vary quite a bit, whereas the variation between the groups is not that great. -Suppose you decide to take a cluster sample. However, you don't really know exactly how many people make up this population, would you still be able to take your sample?

A short questionnaire is to be given to a sample of people. The questionnaire involves the topic of abortion. The woman who will hand out the questionnaire is a big pro-life supporter and on the day of the survey shows up with pamphlets and picket-signs expressing her opinion. What type of bias may this cause?

When a representative sample is selected but respondents give answers that are different from their true opinions, the problem is called

Which one of the following statements is true about sample size and margin of error?

Both cluster and stratified sampling rely on sub-groups in the population. If the sub-groups are all very similar (they can all be considered mini-populations), which sampling method would be preferred?

On a chilly spring afternoon, 10 lab sections of a statistics class all have full attendance. The 10 lab sections each have the same number of students attending. A survey is about to be administered to a sample of the students. It has been decided to first randomly select 3 of the 10 lab sections and then give the evaluation to a simple random sample of 25% of the students in those selected lab sections. What sampling technique is being used for this survey?

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 cluster random sample, using flights as the cluster.