Question 1

In a single-group before-after research design, changes that occur in the participants over time but which are not related to the independent variable are known as which of the following?

Accepted Answer

Maturation refers to the natural or biological changes that occur in participants over time, which are not related to the independent variable being studied. This can include aging, learning, or other developmental processes that might influence the outcome of the study independently of the experimental intervention.

Question 2

Which of the following is NOT a quasi-experimental research design?

Accepted Answer

Matched-participant design is not a quasi-experimental design; it is a type of experimental design where participants are matched on certain variables to control for those variables.

Question 3

A researcher studies the cognitive development of a single group of children by measuring them in kindergarten, fourth grade, and seventh grade. Which type of design is being used?

Accepted Answer

This is a longitudinal study because it follows the same group of children over a period of time, observing their cognitive development at different ages or stages.

Question 4

Researchers compared college students who reported they had smoked marijuana at least fifteen days a month with similar students who said they smoked five days a month at most. A day after going without marijuana, the heavy users performed significantly worse on tasks that involved sustaining and shifting attention. The research design is

Accepted Answer

The research design is a comparison-group design because it involves comparing the performance of two distinct groups of participants (heavy marijuana users vs. light or infrequent users) on specific tasks. This design allows for the examination of differences between groups under different conditions or treatments.

Question 5

Quasi-experimental research designs are so named because

Accepted Answer

Quasi-experimental designs are called so because they involve a grouping for the independent variable, but unlike true experiments, they do not use random assignment to create these groups.

Question 6

Longitudinal designs are to cross-sectional designs as

Accepted Answer

Longitudinal designs, like before-after designs, track changes over time within the same subjects, whereas cross-sectional designs, similar to comparison-group designs, compare different groups at one point in time.

Question 7

An experimenter is interested in the influence of taking a one-semester-long test preparation course on performance on the Scholastic Aptitude Test (SAT). She contacts high school students who have and who have not taken the course and compares their scores on the SAT exam. She finds that the students who have taken the course score significantly higher on the test. Which of the following represents the principal threat to the internal validity of this experiment?

Accepted Answer

The principal threat to the internal validity in this scenario is selection. This is because the experimenter is comparing two groups of students (those who have taken the test preparation course and those who have not) without randomly assigning them to these groups. This non-random assignment means that there could be pre-existing differences between the groups that are responsible for the observed differences in SAT scores, rather than the test preparation course itself.

Question 8

Which of the following represents the greatest limitation to drawing conclusions from a single group design?

Accepted Answer

A single group design lacks a control group, making it difficult to determine if changes in the participants are due to the experience or other factors.

Question 9

A researcher tests the effects of a skills enhancement program by measuring the change in social adjustment of a group of handicapped children before and after they have completed the program against a change in adjustment over the same time period for an equivalent group of children who had not participated in any therapy. The children who went through the program showed significantly greater increase in social adjustment functioning over time. The research design is

Accepted Answer

The design is a comparison-group before-after because it involves comparing changes in social adjustment between two groups (those who participated in the program and those who did not) before and after the intervention.

Question 10

Research designed to study intervention programs with the goal of determining whether the programs are effective in helping the people who make use of them is called

Accepted Answer

Program evaluation research focuses on assessing the effectiveness of intervention programs to determine their impact and effectiveness for participants.

Question 11

Which of the following are threats to internal validity of the single-group before after design?

Accepted Answer

All of the above options (A: Retesting threats, B: Attrition threats, C: Maturation threats) are threats to the internal validity of a single-group before-after design. Retesting threats occur when the pretest influences the posttest scores. Attrition threats arise when participants drop out of the study, potentially leaving a non-representative sample. Maturation threats involve changes in participants over time that are unrelated to the intervention.

Question 12

A student who is participating in a long term research project decides to stop participating and does not inform the experimenter of his decision. This is an example of which of the following threats to validity?

Accepted Answer

Attrition refers to the loss of participants from a study over time, which can threaten the validity of the results if the reasons for participants dropping out are related to the study itself or if the dropout rate is uneven across groups. In this case, the student's decision to stop participating without informing the experimenter is a clear example of attrition.

Question 13

In research that is conducted over a period of time, the participants naturally get older. If the researcher is not interested in the effects of age on the dependent variable, then the changes in age pose which of the following threats to the validity of the research?

Accepted Answer

Maturation refers to the natural changes that occur in participants over time, including aging, which can affect the outcomes of the study if the research is not specifically interested in the effects of age. This can threaten the internal validity of the study by confounding the results with changes that are not related to the experimental manipulation.

Question 14

An experimenter is interested in the influence of taking a one-semester-long test preparation course on performance on the Scholastic Aptitude Test (SAT). She contacts high school students who have and who have not taken the course and compares their scores on the SAT exam. She finds that the students who have taken the course score significantly higher on the test. The research design is

Accepted Answer

The research design is a comparison-group design because it involves comparing two groups of participants (those who have taken the test preparation course and those who have not) on their performance on the SAT. There is no manipulation of variables or assignment to conditions by the experimenter, which distinguishes it from an experimental design. Additionally, there is no before-and-after measurement for the same group, which rules out the before-after designs.

Question 15

Research that uses two groups of individuals, one of which has had and one of which has not had the experience, is known as which of the following?

Accepted Answer

A comparison-group design involves comparing two groups of individuals: one that has had a particular experience and one that has not, to assess the effects of that experience.

Question 16

An experimenter decided to test the effects of a new training program by comparing the motivation of twenty employees who had participated in the program against an equivalent group of twenty employees who had not gone through any training at all. The employees were measured when they had completed the program and it was found that those who had gone through the program had much greater on-the-job motivation than those who had not. It was concluded that the difference in motivation was due to the content of the training program. The research design is

Accepted Answer

The research design is a comparison-group design because it involves comparing two groups of employees (those who participated in the training program and those who did not) on their levels of motivation without manipulating variables or controlling for all potential confounding variables. There is no mention of measuring motivation before the training, so it cannot be considered a before-after design.

Question 17

Threats to internal validity that occur due to the potential influence of changes in the social climate during the course of a study are called

Accepted Answer

History threats to internal validity occur when external events happen during the course of a study that may affect participants' responses or behaviors, thus influencing the study's outcomes. These are not related to the experimental manipulation itself but to the timing of other events in the world or the participants' lives.

Question 18

Which of the following statements is true about quasi-experimental designs?

Accepted Answer

Quasi-experimental designs do not manipulate the independent variable but rather measure it as it naturally occurs, making them more akin to correlational research than true experimental designs, where the independent variable is manipulated to observe its effect on a dependent variable.

Question 19

Quasi experimental designs are usually analyzed using

Accepted Answer

Quasi-experimental designs often involve comparing group means, which is typically analyzed using ANOVA (Analysis of Variance).

Question 20

An experimenter is interested in the influence of taking a one-semester-long test preparation course on performance on the Scholastic Aptitude Test (SAT). She contacts high school students who have and who have not taken the course and compares their scores on the SAT exam. She finds that the students who have taken the course score significantly higher on the test. The appropriate statistical test is

Accepted Answer

The appropriate statistical test for comparing means of two or more groups (in this case, those who have taken the test preparation course and those who have not) on a continuous outcome (SAT scores) is the one-way ANOVA (Analysis of Variance).

Quiz 14: Quasi-Experimental Research Designs