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In the context of this study, identify the independent variable, the dependent variable, and the confounding variable. Explain how the confounding variable behaves systematically in relation to the independent variable, and explain why this prevents the researcher from drawing a clear cause-and-effect conclusion about the app's effectiveness.
Case context: A researcher is conducting a study to investigate whether a new mindfulness training app improves academic performance in college students. She recruits 100 students and allows them to choose which group to join: Group A uses the mindfulness app for 20 minutes daily, while Group B receives no training. At the end of the semester, the researcher measures each student's GPA. However, she discovers that students who chose Group A had a substantially higher average baseline intelligence and motivation level prior to starting the study than students who chose Group B.
Question: In the context of this study, identify the independent variable, the dependent variable, and the confounding variable. Explain how the confounding variable behaves systematically in relation to the independent variable, and explain why this prevents the researcher from drawing a clear cause-and-effect conclusion about the app's effectiveness.
Sample answer: The independent variable is the use of the mindfulness training app (Group A vs. Group B), and the dependent variable is academic performance measured by GPA. The confounding variable is the baseline intelligence/motivation of the students. This extraneous variable varies systematically with the independent variable because students with higher baseline intelligence and motivation selected into Group A, meaning intelligence differs on average across the levels of the independent variable. This prevents a clear causal conclusion because the higher GPA in Group A could be explained by their higher baseline intelligence/motivation rather than the mindfulness app.
Key points:
- Identify the independent variable as the use of the mindfulness training app versus no training.
- Identify the dependent variable as academic performance (GPA).
- Identify baseline intelligence and motivation as the confounding variable.
- Explain that the confounder varies systematically because baseline intelligence/motivation differs on average across the levels of the independent variable due to participant choice.
- Explain that this systematically varying extraneous variable provides an alternative explanation for GPA differences, preventing a clear cause-and-effect conclusion.
Rubric: The student must correctly identify the independent variable (app use), dependent variable (GPA), and confounding variable (baseline intelligence/motivation). The response must explain that the confounder varies systematically because participants self-selected into groups, resulting in an unequal distribution of intelligence. Finally, it must explain that baseline intelligence serves as an alternative explanation for GPA differences, confounding the causal effect of the app.
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Research Methods in Psychology - 4th American Edition @ KPU
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