Chapter 4 Test MCQ Portion

Researchers in Canada performed an experiment with university students to examine the effects of in-class laptop use on student learning. All volunteers in the study were asked to attend a university style lecture and take notes with their laptops. Half of the participants were assigned to complete other non-lecture related online tasks during the lecture. These tasks were meant to imitate typical student Web browsing during classes. The remaining students simply took notes with their laptops. To assign the treatments, the researchers printed 40 papers with instructions (20 with multitasking and 20 without), shuffled them, and handed them out at random to students in the classroom. At the end of the lecture, all participants took a comprehension test to measure how much they learned from it. The results: students who were assigned to multitask did significantly worse than students who were not assigned to multitask.

Which of the following lists the number of explanatory variables, number of treatments, and number of experimental units (in this order)?

• 1, 2, 40

• 2, 4, 40

• 1, 2, 20

• 2, 4, 20

• 2, 2, 40

Researchers in Canada performed an experiment with university students to examine the effects of in-class laptop use on student learning. All volunteers in the study were asked to attend a university style lecture and take notes with their laptops. Half of the participants were assigned to complete other non-lecture related online tasks during the lecture. These tasks were meant to imitate typical student Web browsing during classes. The remaining students simply took notes with their laptops. To assign the treatments, the researchers printed 40 papers with instructions (20 with multitasking and 20 without), shuffled them, and handed them out at random to students in the classroom. At the end of the lecture, all participants took a comprehension test to measure how much they learned from it. The results: students who were assigned to multitask did significantly worse than students who were not assigned to multitask.

Based on the design of the study, which of the following is the most appropriate conclusion?

• Multitasking causes learning to be hindered for all students in this study.

• Multitasking causes learning to be hindered for all students at this university.

• There is not enough information to make any conclusions based on this study.

• There is an association between multitasking and learning for all students at this university.

• There is an association between multitasking and learning for all students in this study.

Researchers want to investigate if students retain more information if it printed on blue paper rather than white paper. They recruit 100 elementary students, 100 middle school students, and 100 high school students to participate. The researchers then randomly assigned half of the elementary students, half of the middle school students, and half of the high school students to receive the information on blue paper. The remaining students receive the same information on white paper. Which of the following best describes this experimental design?

• Completely randomized design

• Block design with grade of student as the blocks

• Block design with color of paper as the blocks

• Stratified design with grade of student as the blocks

• Stratified design with color of paper as the blocks

In a large population of books, 43% have red covers. Sally chooses an SRS of 100 books and finds that only 39 are red. Which of the following best describes why Sally didn’t get exactly 43 red books?

• Sally’s sampling method must have resulted in nonresponse bias.

• Sally’s sampling method must have resulted in response bias.

• Sally’s sample size was too small.

• Sally’s sample size was too large.

• Different samples from the same population will give different results.

During assemblies at a particular high school, the gym is divided into four sections. Students sit in one of four sections according to their class (freshman, sophomore, junior, senior). In each section, there are many rows where students sit. To estimate the proportion of students who enjoyed the assembly, members of student government randomly select 5 rows in the gym and survey each student in the selected rows. Which sampling method did the students use?

• Convenience sample

• Voluntary response sample

• Simple random sample

• Stratified random sample

• Cluster sample

A teacher wants to use a table of random digits to select a simple random sample of 3 unique students (without replacement) from a class of 38 students. Each student is numbered from 01 to 38. Using the random digits below, which students are included in the sample?

17835 84235 77413 50329 54889 15810 99573

• 01, 07, 08

• 17, 35, 03

• 17, 83, 58

• 17, 35, 35

• 17, 84, 77

An apartment complex is made up of 10 buildings with 12 apartments in each building. The manager wants to select a sample of apartments to gauge interest in a proposed improvements to the swimming pool. If the manager selects 20 apartments by randomly selecting 2 apartments from each building, what kind of sample did the manager obtain?

• Convenience sample

• Voluntary response sample

• Simple random sample

• Stratified random sample

• Cluster sample

Do product labels influence customer perceptions? To find out, researchers recruited over 500 adults and asked them to estimate the number of calories, amount of added sugar, and amount of fat in a variety of food products. Half of the subjects were randomly assigned to evaluate products with the word “Natural” on the label while the other half were assigned to evaluate the same products without the “Natural” label. On average, the products with the “Natural” label were judged to have significantly fewer calories. Based on this study, it is reasonable to conclude that including the word “Natural” on the label causes a reduction in estimated calories?

• No, because the adults weren’t randomly selected from the population of all adults.

• No, because there wasn’t a control group for comparison.

• No, because association doesn’t imply causation.

• Yes, because the adults were randomly assigned to the treatments.

• Yes, because there were a large number of adults involved in the study.

Some news organizations maintain a database of customers who have volunteered to share their opinions on a variety of issues. Suppose that one of these databases includes 9000 registered voters in California. To measure the amount of support for a controversial ballot issue, 1000 registered voters in California are randomly selected from the database. Which of the following is the largest population to which the results of this survey should be generalized?

• The 1000 people in the sample.

• The 9000 registered voters from California in the database.

• All registered voters in California.

• All California residents.

• All registered voters in the United States.

• A census because all roses are assigned to a container.

• An experiment with a completely randomized design.

• An experiment with a randomized block design, with blocking by type of water.

• An experiment with a matched-pairs design.

• An observational study.