Seeing Through Statistics 4th Edition by Jessica M. Utts – Test Bank

Seeing Through Statistics 4th Edition by Jessica M. Utts – Test Bank

CHAPTER 4

How to get a good sample

SECTION 4.1

common research strategies

FREE RESPONSE QUESTIONS

1. What is the most important advantage of using a randomized experiment vs. an observational study, in terms of the statistical results?

Answer:  Randomized experiments, unlike observational studies, often allow us to determine cause and effect. In observational studies, you cannot assume that the explanatory variable of interest is the only one that may be responsible for any observed DIFFERENCES in the outcome variable.

1. Name one advantage that observational studies have over experiments.

ANSWER: Researchers are not required to induce artificial behavior. participants are simply observed doing what they would do naturally; therefore the results may be more readily extended to the real world.

1. What is the most important limitation of a case study?

Answer:  Only one or a small number of individuals is studied. You cannot assume the findings can be extended to any person or situation other than the one(s) studied.

1. Why do researchers conduct experiments that are randomized (that is, participants are randomly assigned to the groups being compared)?

Answer:  With randomization, Other variables that may affect the outcome variable should be similar across all of the groups being compared. Then any large enough differences in the outcome variable can be attributed to the explanatory variable.

Multiple Choice QUESTIONS

1. Which of the following is not an example of a common type of research strategy as discussed in your textbook?
   1. Sample surveys
   2. Randomized experiments
   3. Case studies
   4. All of the above are examples of common types of research strategies

Answer: d

1. Which of the following is a research strategy that involves the researcher manipulating the participants’ environment in some way?
   1. Sample survey
   2. Randomized experiment
   3. Observational study
   4. None of the above

Answer: b

1. Which of the following news story excerpts describes the results of a meta-analysis?
   1. “A recent analysis of eight international studies found that…”
   2. “A recent long-term study using 100,000 participants found that…”
   3. “This single study contained 10 parts; each part used a different type of statistical analysis to get the results. The results showed that…”
   4. None of the above.

Answer: a

1. When you read the results of a scientific study, which of the following should you do first?
   1. Determine which type of research strategy was used (observational study, randomized experiment, etc.)
   2. Look at the results and decide whether they make sense or not.
   3. Jump to the part where they show the data, and see if was collected properly.
   4. Decide if the results apply to your life.

Answer: a

fILL-in-the-blank QUESTIONS

1. In an experiment, you measure the result of the feature being manipulated, called the __________ variable, on an outcome, called the __________ variable.

Answers (respectively):  explanatory; outcome (or response)

1. A (an) __________ study is an in-depth examination of one or a small number of individuals.

Answer:  case

SECTION 4.2

Defining a common language

FREE RESPONSE QUESTIONS

For Questions 11-16 use the following narrative

Narrative: Boat show

The annual Vacation & Boat Show in Columbus, Ohio offers four types of attractions: boats, fishing gear, outdoor equipment, and vacation planning services. Tickets sell for $6 per person, and children under 5 get in free. This year the show organizers want to find out which attraction was most popular, so they surveyed 100 people at random who attended the show, and asked them. The results showed that 67% of them liked the boats best.

1. {Boat show narrative} Specify who/what the units are in this study.

Answer:  The units are the boat show participants.

1. {Boat show narrative} Specify the population.

ANSWER: all of the people who attended the Vacation and Boat show in Columbus, Ohio this year.

1. {Boat show narrative} Specify the sample.

Answer: the 100 boat and vacation show participants who were randomly selected to participate in the survey.

1. {Boat show narrative} Is there a practical and accurate way to get a sampling frame for this population? If yes, explain how. If no, explain why not.

Answer:  Yes. How: any reasonable answer ok. Example: since tickets were purchased, ticket stubs could be saved and names/ticket numbers drawn to participate in the survey (and maybe get their admission refunded for participating). This assumes children under 5 don’t vote.