Podcast
Questions and Answers
What is a significant issue when experimental participants are run in separate groups compared to control participants?
What is a significant issue when experimental participants are run in separate groups compared to control participants?
- Lack of experimental control
- Improved external validity
- Potential history effects (correct)
- Increased sample size
What does instrumentation refer to in the context of internal validity?
What does instrumentation refer to in the context of internal validity?
- The choice of independent variable
- Increased participant engagement
- Random assignment to groups
- Changes in measurement procedures (correct)
What can be done to minimize the threat of instrumentation in research?
What can be done to minimize the threat of instrumentation in research?
- Utilize a single method of data collection
- Regularly change the independent variable
- Allow conditions to be run at varied times
- Conduct careful training and monitor observers (correct)
Maturation as a threat to internal validity primarily refers to what?
Maturation as a threat to internal validity primarily refers to what?
What is mortality in the context of research studies?
What is mortality in the context of research studies?
What does maturation primarily refer to in the context of behavioral studies?
What does maturation primarily refer to in the context of behavioral studies?
How can maturation bias be mitigated in a study comparing the effects of therapy on children's speech?
How can maturation bias be mitigated in a study comparing the effects of therapy on children's speech?
What is a potential problem when experimental trials are not evenly distributed during an experimental session?
What is a potential problem when experimental trials are not evenly distributed during an experimental session?
What is a major threat to internal validity in experimental studies involving different groups?
What is a major threat to internal validity in experimental studies involving different groups?
What experimental design technique can help address the issue of maturation effects during an experiment?
What experimental design technique can help address the issue of maturation effects during an experiment?
What is the primary purpose of random assignment in research studies?
What is the primary purpose of random assignment in research studies?
Which design method can be used when random assignment is not feasible?
Which design method can be used when random assignment is not feasible?
Which of the following best represents a potential threat to internal validity when comparing treatment effects between genders?
Which of the following best represents a potential threat to internal validity when comparing treatment effects between genders?
What should researchers do to assess changes expected without treatment?
What should researchers do to assess changes expected without treatment?
Which of the following is NOT listed as a common threat to internal validity?
Which of the following is NOT listed as a common threat to internal validity?
Flashcards
Selection Bias
Selection Bias
A threat to internal validity where differences in participants' characteristics, not the treatment, may cause observed changes in the dependent variable.
Maturation
Maturation
A threat to internal validity that occurs due to natural changes within the participant over time, independent of the treatment.
Short-term Maturation
Short-term Maturation
A type of maturation that occurs during an experimental session, like fatigue or boredom.
Counterbalancing
Counterbalancing
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Control Group
Control Group
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Instrumentation Threat
Instrumentation Threat
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Mortality Threat
Mortality Threat
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History Threat
History Threat
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Selection by Maturation
Selection by Maturation
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Selection Threat
Selection Threat
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Maturation Threat
Maturation Threat
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Cross-Sequential Design
Cross-Sequential Design
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Study Notes
Randomized Experiments
- Controlling and Manipulating Variables:
- Researchers manipulate independent variables to observe their effect on dependent variables.
- Researchers control extraneous variables to isolate the effect of the manipulated variable.
- Random Assignment:
- Random assignment ensures each participant has an equal chance of being assigned to any of the conditions.
- Random assignment aims to equate groups on all other variables, enabling researchers to infer causal relationships more reliably.
- Threats to Internal Validity:
- Selection: Pre-existing differences between groups.
- Maturation: Natural changes within participants over time.
- History: External events that occur alongside the treatment.
- Instrumentation: Changes in measuring instruments or procedures during the study affecting results.
- Mortality: Participants dropping out of the study unequally across groups.
Independent Variables
- Independent Variables That Vary Within and Between Participants:
- Independent variables can be manipulated either between participants (different participants experience different levels) or within participants (the same participants experience all the levels).
- Construct Validity of Independent Variables:
- Researchers create operational definitions that clearly specify the manipulation and its intended theoretical construct for a given independent variable.
- Manipulation checks examine how well the independent variable is manipulating the intended construct.
Alternative Experimental Designs
- Randomized Two-Group Design:
- Participants are randomly assigned to either a treatment or control group.
- Measurements are taken after the treatment, comparing the treatment and control groups' outcomes.
- Pretest-Posttest Two-Group Design:
- Participants measured before and after the treatment.
- Comparing pretest and posttest scores within each group and between groups provide valuable insights.
Repeated Measures Designs
- Repeated measures designs utilize the same participants in different conditions or for different measurements.
- This often leads to more efficient use of participants.
- However, the order effect or practice effect, which can bias the results, is something that should be addressed.
Analyzing Data From Experimental Designs
- Statistical analysis, like ANOVA, is essential for comparing group mean differences to determine if the treatment effects are significant.
Strengths and Weaknesses of Randomized Experiments
- Strengths:
- High internal validity: Enables researchers to infer cause-and-effect relationships by isolating treatment effects.
- Control of extraneous variables.
- Weaknesses:
- External Validity: Results may not generalize beyond the specific conditions of the experiment.
- Artificiality: Laboratory settings can sometimes lack realism, potentially limiting generalizability.
- Representative Samples: Samples are often limited to undergraduates making analysis difficult.
- Limited Descriptive Data: Information about frequencies or probabilities for certain behaviours is usually limited.
Further Reading Suggestions
- Include specific resources and websites for further study.
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Description
Explore critical aspects of internal validity and experimental design in this quiz focused on Chapter 5 of Research Methods in Psychology. You'll tackle questions about concepts such as maturation, mortality, and instrumentation, and discover how to mitigate these issues in research studies. Test your understanding of how different experimental designs can influence research outcomes.
