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According to the definition of a true experiment, explain what is required regarding the independent variable. In your response, contrast this requirement with merely comparing pre-existing groups and explain why this distinction is crucial for the validity of the results.
Question: According to the definition of a true experiment, explain what is required regarding the independent variable. In your response, contrast this requirement with merely comparing pre-existing groups and explain why this distinction is crucial for the validity of the results.
Sample answer: A true experiment requires the researcher to actively intervene and manipulate the independent variable. Simply comparing pre-existing groups does not constitute manipulation. This active manipulation is essential because it is crucial for eliminating potential alternative explanations, such as confounding variables, for the results.
Key points:
- A true experiment requires the researcher to actively intervene and manipulate the independent variable.
- Comparing pre-existing groups does not constitute manipulation.
- Active manipulation is crucial for eliminating potential alternative explanations/confounders.
Rubric: Graders should look for three main components: (1) state that a true experiment requires active intervention and manipulation of the independent variable; (2) explain that comparing pre-existing groups is not manipulation; and (3) explain that active manipulation is necessary to eliminate alternative explanations or confounding variables.
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Research Methods in Psychology - 4th American Edition @ KPU
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Inability to Manipulate Variables
What is a critical requirement regarding the independent variable for a study to be classified as a true experiment?
A researcher wants to study whether journaling improves mental health. She recruits 200 participants and finds that 95 of them already keep a daily journal while the remaining 105 do not. She measures each group's mental health scores and compares the results. This study qualifies as a true experiment because it compares two distinct groups on a dependent variable.
Match each research scenario with the correct methodological classification and rationale regarding the use of active manipulation.
A researcher notices that honors students listen to classical music more often and have higher grades than non-honors students. To determine if music causes better performance, the researcher must design an experiment. Arrange the steps of this design to show how active manipulation logically rules out pre-existing differences (like academic ability) as alternative explanations.
A researcher evaluating the validity of a study on 'brain-training apps' rejects the claim that the apps cause memory improvement because the study merely compared regular users to non-users. The researcher notes that for a true experiment, the design requires active _____, a step necessary to rule out pre-existing differences in motivation or cognitive ability as alternative explanations for the results.
A researcher is designing a study to test if 'mindfulness meditation' increases empathy. Currently, they observe that members of meditation clubs score higher on empathy scales than non-members. To create a true experiment that utilizes active manipulation to eliminate the alternative explanation that 'naturally empathetic' people are simply more drawn to meditation, which protocol should the researcher construct?
Merely comparing pre-existing groups of participants (such as comparing individuals who already keep a journal with those who do not) constitutes active manipulation of the independent variable in a true experiment.
Match each concept related to research methods with the statement that best explains its role in determining whether a study is a true experiment.
A psychologist notices that people who voluntarily practice mindfulness meditation report lower levels of depression than non-meditators and concludes that meditation reduces depression. A methodological critique of this study would point out that she never _____ the independent variable—the defining step that separates a true experiment from a correlational comparison—and therefore cannot eliminate the possibility that naturally less-depressed individuals are simply more inclined to choose meditation in the first place.
A peer reviewer is evaluating a published study that concludes 'journaling causes reduced anxiety.' The study compared anxiety scores of people who already kept a daily journal with those who did not. Arrange the following evaluative steps in the most logical order to judge whether the causal conclusion is warranted.
According to the definition of a true experiment, explain what is required regarding the independent variable. In your response, contrast this requirement with merely comparing pre-existing groups and explain why this distinction is crucial for the validity of the results.
Based on the concepts of active manipulation, explain why this study cannot be classified as a true experiment, and diagnose how potential confounding variables could explain the differences in cognitive performance.
Imagine you want to study whether keeping a daily journal reduces stress. If you observe that people who already keep journals are less stressed than those who do not, how would you design a study that applies active manipulation to test this relation as a true experiment?