Question 1

Which of the following is true of propensity score matching?

Accepted Answer

Propensity score matching is a technique used in observational studies where individuals in the treatment group are matched with individuals in the control group based on their propensity score, which is the probability of receiving the treatment based on a set of relevant covariates. This technique allows for individuals to be matched on multiple variables to make the groups more comparable. Option A is incorrect because propensity score matching does not use random assignment. Option C is incorrect because propensity score matching does not pertain to studying persons of different ages, and option D is incorrect because extreme scoring is not a criterion for selection in propensity score matching.

Question 2

A researcher wants to test the effect of alcohol on driving performance. Participants first drive through an obstacle course before drinking any alcohol. The participants then drink 8 ounces of alcohol and drive the course again. After each trial, the number of traffic cones hit is recorded. The researcher finds that the number of traffic cones hit is greater before rather than after the participants drank the alcohol. What may best account for the change in performance?

Accepted Answer

The testing effect refers to the phenomenon where participants' performance is influenced by previous exposure to the test. In this case, driving through the obstacle course before drinking any alcohol may have acted as a practice round, allowing participants to become more familiar with the course and improve their driving skills. Therefore, their performance may have improved due to the testing effect, rather than the alcohol having a negative impact on their driving ability.

Question 3

Over time, human observers may become fatigued or change the standards on which observations are based. When this change in measurement occurs over time, a researcher might attribute it to _____.

Accepted Answer

Instrument decay refers to a change or degradation in the quality of measurement due to factors such as wear and tear, loss of sensitivity or bias. This can result in a change in measurement over time, even though the phenomena being measured remains stable.

Question 4

Selection differences in the nonequivalent control group design are:

Accepted Answer

Selection differences in the nonequivalent control group design can threaten the internal validity of the study because it is difficult to determine whether the differences observed between the groups are due to the independent variable or to the pre-existing differences between the groups. Therefore, it is important for researchers to carefully match the groups on relevant variables as much as possible or to use statistical techniques to control for potential confounders in the analysis.

Question 5

A graduating college student takes the Graduate Record Exam and scores high marks. Six months later the student retakes the exam after completing all undergraduate coursework, but scores relatively low. Other than the boring coursework, what is most likely to account for the lower scores?

Accepted Answer

Regression toward the mean is the most likely cause for the lower scores on the second exam. This phenomenon suggests that extreme scores, whether high or low, will become less extreme over time and move toward the mean, or average, score on subsequent testing. Thus, the student's low score on the second exam can be explained by the fact that their first score was unusually high, and the second score reflects a return to their actual ability level.

Question 6

In the context of one-group pretest-posttest design, maturation effects occur when:

Accepted Answer

Maturation effects occur when participants naturally change over time, such as becoming bored or fatigued, which can affect their behavior and affect the results of the study. Option A describes the testing effect, option C describes a confounding variable, and option D describes instrumentation effects.

Question 7

A way to improve the interrupted time series design is to use a _____ design.

Accepted Answer

A control series design enhances an interrupted time series design by adding a comparison or control group, which helps in isolating the effect of the intervention from other external factors that might influence the outcome.

Question 8

A school administrator wants to examine the effect of student lockers on class tardiness. He compares tardiness records of a school with no lockers to a school with lockers. What type of research design is this?

Accepted Answer

This study involves comparing two groups (the school with lockers and the school without lockers), but the groups are not equivalent since they differ in the presence of lockers. Therefore, this is an example of a nonequivalent control group design.

Question 9

Selection differences are less likely to occur when researchers:

Accepted Answer

Random assignment controls for selection differences because it ensures that each participant has an equal chance of being placed in either group. Pre-existing groups found in natural settings and self-assignment may lead to selection bias. The nonequivalent control group design also runs the risk of selection differences because the groups are not created through random assignment.

Question 10

Teachers at School A were given a substance abuse knowledge test. During the next four months, the teachers attended training sessions on substance abuse. They were then given the knowledge test again. Similarly, teachers at School B were given the substance abuse knowledge test, and four months later they were given the test again. What kind of design was used in this research?

Accepted Answer

This research design is a nonequivalent control group pretest-posttest design because it involves comparing two groups (School A and School B) where one group receives an intervention (substance abuse training for School A) and both groups are tested before and after the intervention, without random assignment to groups.

Question 11

The serious flaw associated with the nonequivalent control group design is that ____ occur.

Accepted Answer

The serious flaw associated with the nonequivalent control group design is that selection differences can occur. This means that the groups being compared may differ in ways that affect the outcome, which cannot be attributed to the intervention being studied. In other words, it is possible that any observed differences between the groups are due to factors other than the treatment, making it difficult to draw valid conclusions about its effectiveness.

Question 12

Which of the following is true of a nonequivalent control group design?

Accepted Answer

In a nonequivalent control group design, the two groups are not randomly assigned, and therefore selection differences are likely to arise. This makes it more difficult to infer causation because differences between groups may be due to preexisting differences rather than the manipulation of the independent variable.

Question 13

Regression toward the mean refers to the fact that:

Accepted Answer

Regression toward the mean refers to the phenomenon where extreme scores on a variable tend to move or regress towards the average or mean score upon retesting. This is due to the fact that extreme scores are likely to be caused by random, unrepresentative factors that are unlikely to persist upon retesting. For example, if a group of students who score very high on a test one year are retested the next year, their scores are likely to regress toward the mean.

Question 14

A human resources psychologist is interested in the effect of work schedule on job satisfaction. She compares satisfaction scores of workers who work five 8-hour shifts with workers who work four 10-hour shifts. Which of the following types of design has the manager employed?

Accepted Answer

The human resources psychologist has employed a nonequivalent control group design, where the two groups being compared (workers who work five 8-hour shifts and those who work four 10-hour shifts) are not randomly assigned and there is no pretest. The comparison is made using a posttest to assess job satisfaction.

Question 15

A study is conducted in which the attitudes of the staff of a rehabilitation center are assessed; then the staff is exposed to an attitude-change manipulation, and attitudes are assessed again. Another rehabilitation center of similar size is also chosen; attitudes there are measured, and then assessed again after manipulation. This quasi-experimental design is called a _____ design.

Accepted Answer

This quasi-experimental design is called a nonequivalent control group pretest-posttest design because there is no random assignment to groups and the two rehabilitation centers are not equivalent in all aspects. The pretest-posttest design is used to compare the attitudes before and after the manipulation of the independent variable, and the use of a control group helps to control for alternative explanations for the changes in attitudes. The other options are not appropriate for this design as they involve different types of experimental designs or do not include a control group.

Question 16

What is the advantage of the pretest in the nonequivalent control group pretest-posttest design?

Accepted Answer

The pretest in the nonequivalent control group pretest-posttest design allows researchers to examine changes from pretest to posttest scores within each group, which can help control for individual differences in the groups. This advantage is particularly important when groups are not equivalent at the start of the study. Option A is incorrect because while the pretest may accustom participants to the procedures, this is not necessarily an advantage of the design. Option B is incorrect because if participants score higher on a posttest after experiencing a pretest, this could be due to practice effects rather than the treatment itself. Option D is incorrect because the study should not be discontinued immediately based solely on pretest scores.

Question 17

The use of existing natural groups of participants often results in:

Accepted Answer

Using existing natural groups of participants may result in nonequivalent groups because the groups may differ in important ways that could affect the outcome of the study. For example, if a study on the effectiveness of a new medication is conducted on patients from different hospitals, the hospitals may have different patient populations with varying demographics, health conditions, and treatments that could affect the results.

Question 18

The interrupted time series design involves:

Accepted Answer

The interrupted time series design involves making observations over an extended period of time before and after a treatment is instituted. This allows researchers to examine any changes in the outcome variable that may be associated with the intervention. Time is used as a variable in this design, but it is not the independent variable. Treatment and control groups may or may not be used in this design, so option D is not accurate. Option A describes a pre-post test design and is not specific to interrupted time series.

Question 19

_____ usually occurs when participants who form the two groups in an experiment are chosen from existing natural groups.

Accepted Answer

Selection bias occurs when participants are chosen from existing natural groups, leading to non-random assignment and potential differences between groups.

Question 20

In one-group pretest-posttest design, which of the following will occur whenever researchers gather a set of extreme scores taken at one time and compare them with scores taken at another point in time?

Accepted Answer

Whenever extreme scores are selected at one time and compared with scores taken at another point in time, there is often a tendency for the extreme scores to regress or move towards the mean. This occurs due to the fact that extreme scores are often a result of random fluctuation or measurement error and are thus unlikely to be replicated. As a result, when extreme scores are retested, they tend to move closer to the average score.

Quiz 11: Single-Case, Quasi-Experimental, and Developmental Research