Exam 5: Sampling: Surveys and How to Ask Questions

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

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 20 students among all students taking a foreign language class that year, the sampling method is a

Which of the following is not true about drawing a simple random sample from a population?

Explain the difference between an open question and a closed question.

A class consists of 30 students and the instructor wants to take a simple random sample of 5 students from this class. The students are labeled 01 to 30 for the selection process. Which of the following possible samples of size n = 5 is most likely to be selected?

A survey-taker randomly selected 1000 students who were studying in the library and found that 90% of these students were in favor of longer library hours. The results of this study, if applied to all students in the university, are questionable because of

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 would be the approximate margin of error if the researcher randomly sampled 2000 adults?

People claim that only 5% of the students who take the introductory statistics course will continue their education in statistics. The Statistics Department believes that this value is too low and decides to take a sample of 20 students out of the 315 students registered that semester. Of the 20 students, 7 (or 35%) say they will continue to study more statistics. It turns out that the 20 students selected for this study were those that received the highest scores on the first quiz. The results of this study, if applied to all students who take the introductory statistics course, are questionable because of

Define the purpose of inferential statistics.

Two researchers are each conducting a study to estimate a certain population proportion. Researcher A proposes to take a random sample of n = 1000 units from his population of 1 million units. Researcher B proposes to take a random sample of n = 2000 units from his population of 2 million units. For which researcher will the margin of error be the smallest? Explain.

When the method for selecting subjects produces a sample that does not represent the population of interest, the problem is called

In a random sample of n = 400 people, 40% say they have allergies. The conservative margin of error is reported to be 5%. What is a 95% confidence interval for the percent of the population that has allergies?

A company that produces electronics (stereos, TV's, DVD players, etc.) is thinking about adding an incentive program to the contracts of its employees. To learn about the opinion of its employees regarding this idea, a survey will be sent out to a sample of the employees. To ensure that employees of all three plants are represented in the survey, the statistician decides to take a sample of employees from each of the three plants. At each plant, a list is available of all employees. A 1-in-20 systematic sample will be taken from each plant. What sampling technique is being used to sample the employees?

A class consists of 30 students and the instructor wants to take a simple random sample of 5 students from this class. Which of the following represent the labels that are needed in order to select the sample using a random number table?

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. -If you were to take a sample of these people and would like to utilize these groups in some fashion, which sampling technique should you use?

Consider the following survey question: "Do you agree that the alcohol industry should be banned from targeting the teenage girls in their advertising?" Which of the following types of bias is this question an example of?

Use the following information for questions: First Avenue is in desperate need of repaving. The county road commission would like to survey the people who live along this road. They have a list available of all 176 household addresses along First Avenue with the addresses listed in numerical order by address. -Using the following stream of random digits, determine the first five selected addresses that would be part of the simple random sample of 20 addresses. 16332 40139 64701 46355 62340 22011 47257 74877

A random sample of 2000 students showed that 800 were in favor of more movies on campus. Report the results of this poll using the sample proportion and margin of error.

A random sample of registered 500 voters was taken, and 80% responded that they had voted in the last presidential election. Explain why response bias may be a problem for this survey.

Use the following information for questions: Decide if the sample is representative (or not) of the population for the question of interest. -What is the average daily number of hours of sleep over a one year period? Sample: Hours of sleep for 100 randomly selected students the night before an exam. Population: All students in the university.