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External validity refers to the ______ of research results to other people, settings, and conditions. _________ is a threat to external validity when administration of a pretest affects how subjects react to the treatment.
generalizability
pretest sensitization
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The effects of pretesting on both internal and external validity can be evaluated by using the ________ four-group design.
Solomon
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Another potential threat is an interaction between _______ and treatment, which occurs when people in the sample differ from people in the _______ in terms of some characteristic that makes them respond differently to the independent variable.
selection
population
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________ is another potential threat to external validity and occurs when research participants act differently because they know their behavior is being observed. A subject's behavior might be altered by _______, which are cues in the research setting that communicate to subjects what behaviors are expected of them.
reactivity
demand characteristics
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Multiple treatment _________ threatens a study's external validity when more than one _______ of the IV is administered to each subject. This threat can be controlled by using a Latin square deign ot other type of _________ design.
interference
level
counterbalanced
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When using a _____ groups research design, the effects of an independent variable are assessed by administering each level of the independent variable to a different ________ of subjects and comparing the performance or status of the groups on the ______ variable
between
group
dependent
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When using a ________ subjects (repeated measures) design, the effects of an independent variable are assessed by comparing the performance or status of the same group of subjects on the _______ variable after receiving, at different times, each level of the independent variable.
within
dependent
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In the single-group _______ design, the dependent variable is measured several times before and after the independent variable is applied.
time-series
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The research design that includes two or more independent variables is called a _______ design. An advantage of this type of design is that it allows an investigator to assess the main effects of each independent variable as well as any interaction between those variables.
Factorial
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A(n) ________ effect is the effect of one independent variable on the dependent variable, while a(n) ________ is the effect of one independent variable on the dependent variable at different ________ of another independent variable.
main
interaction
levels
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Two distinguishing characteristics of the single-subject designs are that they include at least two phases - a _________ (no treatment) phase and a _________ phase - and that they involve measuring the _______ variable at regular intervals during each phase of the study
baseline
treatment
dependent
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Three commonly used single-subject designs are the AB design, the reversal design, and the multiple baseline design. The AB design includes one ________(A) phase and one __________(B) phase. The reversal designs extend the AB design by including, at a minimum, two _______ phases and one _______ phase.
baseline
treatment
baseline
treatment
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When using a reversal design, if the subject's performance on the ________ variable follows the predicted pattern (i.e., if it changes in the expected direction after the treatment is applied and withdrawn), a researcher can conclude that changes in the ________ variable are due to the effects of the _______ variable rather than to history, maturation, or other factors.
dependent
dependent
independent
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When it is not ethical or practical to withdraw an effective treatment during the course of a study, an investigator can use the multiple _______ design, which involves sequentially applying the _______ variable to two or more "baselines" - i.e., either to two or more behaviors, settings, tasks, or subjects. An advantage of this design is that once the IV is applied to a baseline, it is not _______ during the study
baseline
independent
withdrawn (removed)
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Dr. Angela Angst is using a repeated measures design to compare the effects of different techniques for reducing free-floating anxiety. To control potential carryover effects, Dr. Angst should use which of the following?
A.Randomized blocking
B.Trend analysis
C.Counterbalancing
D.Point biserial correlation
C
Carryover effects occur in repeated measures designs when the effects of one treatment have an impact on the effects of subsequent treatments. Counterbalancing distributes the carryover effects evenly across the treatment groups so their influence is balanced.
Answer A: Randomized blocks design are used for controlling extraneous variables that are NOT the result of using a repeated measures design.
Answer B: Trend analysis involves one or more quantitative independent variables and the researcher wants to evaluate the shape, pattern, or form of the relationship between independent and dependent variables.
Answer D: The point biserial coefficient is used when one variable is continuous and the other is a true dichotomy.
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An interviewer unintentionally nods whenever research participants answer the questions in ways that confirm the study's research hypothesis. The interviewer's behavior is best described as an example of which of the following?
A.Treatment diffusion
B.Demand characteristics
C.Placebo effect
D.Confirmation bias
B
This question describes a type of reactivity in which the behavior of participants is affected by cues from the researcher indicating what behaviors are expected of them. Cues from a researcher or in the environment that inform participants about the purpose of the study or indicate what behavior is required of them are referred to as demand characteristics.
Answer A: Treatment diffusion (also known as treatment spillover) occurs when participants in one group inadvertently receive (or learn about) the intervention that has been applied to participants in another group.
Answer C: The placebo effect refers to an improvement in physical or mental health that occurs in response to a "fake" treatment (e.g., a sugar pill) typically because the individual expects that the treatment will be effective.
Answer D: Confirmation bias is the tendency to pay attention to information confirming one's current beliefs or preconceptions.
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A psychologist evaluates the effects of a 15-month training program on the conservation skills of preoperational children by administering a measure of conservation to the same group of children before and at the end of training. The psychologist finds that significantly more children are able to conserve after the program than before the program. The biggest threat to this study's internal validity is_____.
A.interaction between selection and treatment
B.interaction between testing and treatment
C.maturation
D.history
C
Internal validity is threatened whenever an investigator cannot maximize the variability of the independent variable, control for extraneous variables, and minimize random error. Maturation threatens internal validity when biological or psychological changes occur within subjects during the course of the study. The length of the training program (15 months) spans a considerable amount of time during the developmental period, which makes it difficult to determine if changes in the DV were because of the IV or the child's typical growth and development.
Answer A: Interaction between selection and treatment is considered a threat to external validity.
Answer B: Interaction between testing and treatment is considered a threat to external validity.
Answer D: While history is a threat to internal validity, it is a threat when an external event systematically affects the status of subjects on the dependent variable; therefore, it is not the best answer.
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In which of the following types of research studies do participants act as their own "controls"?
A.Double-blind
B.Ex post facto
C.Cross-sectional
D.Single-subject
D
In single-subject designs, a researcher compares a participant's behavior during the baseline (no treatment) and treatment phases. When using single-subject designs, participants act as their own no-treatment controls.
Answer A: In a double-blind study design neither the researcher nor the participants know who is receiving a particular treatment.
Answer B: In ex post facto design, the independent variable is not manipulated as it has already occurred.
Answer C: A cross-sectional design involves examining data from a population at one specific point in time.
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A psychologist obtains a statistically significant F-ratio for the interaction between two independent variables (IVs). This means that_____.
A.systematic error weakened the main effect
B.random error weakened the main effect
C.the relationship between a factor and the response differs by the level of the other factor
D.the psychologist should increase the level of significance
C
When an interaction is statistically significant, the relationship between a factor and the response differs by the level of the other factor.
Answer A: When an interaction is statistically significant, it does not suggest systematic error had an impact on the main effect. Instead, it suggests that the relationship between a factor and the response differs by the level of the other factor.
Answer B: When an interaction is statistically significant, it does not suggest random error had an impact on the main effect. Instead, it suggests that the relationship between a factor and the response differs by the level of the other factor.
Answer C: If an interaction effect is already detected at the current level of significance, a psychologist should not increase the level of significance. Increasing the level of significance increases power or the ability to detect an effect, but in this case, an effect has already been detected. Increasing the level of significance also increases the risk of making a Type I error.
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A researcher would use the Solomon four-group design to control which of the following threats to the validity of a research study?
A.Regression to the mean
B.Experimental mortality
C.Maturation
D.Pre-testing effects
D
The Solomon four-group design is used to measure the effects of pretesting on a study's internal and external validity.
Answer A: Regression to the mean is best controlled for by conducting a randomized controlled trial during the design stage.
Answer B: Experimental mortality cannot be directly controlled. Strategies such as trying to prevent dropouts, determining the cause of dropout, and determining whether it contributed to the differences observed can all be helpful in minimizing dropout.
Answer C: Maturation is often controlled by limiting the amount of time between pre and post-tests.
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As applied to research design, "external validity" refers to which of the following?
A.The extent to which a researcher can establish a dependable cause and effect relationship between the treatment and the outcome.
B.The extent to which a researcher can apply or generalize the results of a study to the larger population (i.e., other situations, groups, or events).
C.The degree to which a test measures what is purported or designed to measure.
D.The degree to which a test appears (at face value) to measure what it claims to.
B
External validity is the extent to which we can generalize the results of a study to a larger population.
Answer A: This describes internal validity.
Answer C: This describes construct validity.
Answer D: This describes face validity and is a considered the weakest form of validity because it is subjective.
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