Question 1

Quasi-experimental designs differ from experimental designs in which of the following ways?

Accepted Answer

Quasi-experiments do not use random assignment to assign participants to different conditions, unlike true experiments. This is a key difference that affects how results can be interpreted in terms of causality.

Question 2

When participants are selected for a pretest-posttest design because they have extremely low or extremely high scores on the dependent variable, researchers must be on the lookout for

Accepted Answer

Regression to the mean is a phenomenon that occurs when participants are selected based on extreme scores. Over time, their scores are likely to move closer to the average, which can be mistaken for an effect of the intervention rather than a statistical inevitability.

Question 3

A local history effect occurs

Accepted Answer

A local history effect refers to when groups in a study experience different events or conditions that are not part of the intended experimental manipulation (the quasi-independent variable), which can influence the outcomes of the study. This is distinct from issues related to random assignment, regression to the mean, or the geographic origin of participants.

Question 4

In a nonequivalent control group pretest-posttest design, the greatest threat to internal validity is

Accepted Answer

Local history refers to specific events that occur in the environment of the experimental group but not in the control group during the course of the study. These events can affect the outcome, making it difficult to determine if changes in the experimental group are due to the treatment or to these external events. This is a significant threat to internal validity in nonequivalent control group designs because the groups are not randomly assigned, increasing the likelihood that differences between groups are due to factors other than the treatment.

Question 5

Regression to the mean is most likely to be a threat to internal validity when

Accepted Answer

Regression to the mean is a statistical phenomenon that occurs when a variable that is extreme on its first measurement tends to be closer to the average on its second measurement. This is most likely to threaten internal validity when a sample is specifically chosen because it had unusually low or high scores on the dependent variable, as any subsequent measurement is likely to show a change towards the mean that could be mistakenly attributed to the effect of the experimental manipulation rather than this statistical tendency.

Question 6

When should a one-group pretest-posttest design be used?

Accepted Answer

The answer of When should a one-group pretest-posttest design be...

Question 7

Compared to true experiments, quasi-experiments tend to

Accepted Answer

Quasi-experiments have lower internal validity because they often do not involve random assignment to conditions, making it harder to establish causal relationships.

Question 8

The central threat to the internal validity of a simple interrupted time series design is

Accepted Answer

Contemporary history refers to events occurring around the time of the intervention that could affect the outcome, thus posing a threat to the internal validity of a simple interrupted time series design by confounding the effects of the intervention with those of external events.

Question 9

When the groups in a quasi-experiment were not equivalent at the beginning of the study, _________ may compromise internal validity.

Accepted Answer

Selection bias compromises internal validity in a quasi-experiment when the groups were not equivalent at the beginning of the study. This occurs because participants were not randomly assigned to groups, leading to potential differences between groups that can affect the outcome of the study.

Question 10

The one-group pretest-posttest design is a _______ design.

Accepted Answer

The one-group pretest-posttest design is considered a pre-experimental design because it lacks a control group and random assignment, making it unable to fully address issues of causality.

Question 11

The interrupted time series design with a reversal attempts to address which of the following threats to internal validity?

Accepted Answer

Contemporary history threats to internal validity are addressed by the interrupted time series design with a reversal, as it allows for the observation of effects before, during, and after an intervention, helping to distinguish between the effects of the intervention and external events.

Question 12

In a simple interrupted time series design,

Accepted Answer

In a simple interrupted time series design, the dependent variable is measured multiple times before and after an intervention to assess the intervention's effect. This allows for the observation of patterns over time.

Question 13

Which of the following confounds is most likely in research that studies children over time?

Accepted Answer

Maturation is a confound in longitudinal studies involving children because it refers to the biological and psychological growth and development that occur over time, which can affect the outcomes being measured.

Question 14

A nonequivalent group's posttest-only design is also called a

Accepted Answer

A nonequivalent group's posttest-only design is often referred to as a static group comparison because it involves comparing groups that have not been equivalently assigned.

Question 15

Adding a nonequivalent control group to an interrupted time series design

Accepted Answer

Adding a nonequivalent control group to an interrupted time series design does not eliminate the effects of local history, convert a quasi-experimental design to an experimental design, or require multiple replications. It still leaves potential for confounding variables and does not address all threats to internal validity.

Question 16

Unlike an independent variable, a quasi-independent variable

Accepted Answer

A quasi-independent variable is not directly manipulated by the researcher, unlike an independent variable which is intentionally varied to observe its effect on a dependent variable.

Question 17

Experimental contamination occurs when

Accepted Answer

Experimental contamination occurs when participants in different conditions interact with one another, potentially influencing each other's responses and affecting the study's outcomes.

Question 18

Contemporary history is a problem

Accepted Answer

The answer of Contemporary history is a problem
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Question 19

Which of the following threats to internal validity is present in a one-group pretest-posttest design?

Accepted Answer

All of these answers are correct because in a one-group pretest-posttest design, maturation (changes in participants over time), history (events that occur between the pretest and posttest that are not part of the intervention), and testing effects (effects of taking the pretest on posttest scores) can all threaten internal validity.

Question 20

A researcher is studying the effects of sunspot activity on human emotions. In this study, sunspot activity is the

Accepted Answer

The answer of A researcher is studying the effects of...

Quiz 13: Quasi-Experimental Designs