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Analyze the researchers' concern in light of the fallibility of random assignment. Explain how the safeguards of the scientific process address their situation, and describe what steps the researchers should understand or take regarding their sample size, statistical analysis, and future work to put this concern into perspective.
Case context: A research group is investigating the effects of a new study technique on exam performance. Due to resource constraints, they recruit a small sample of 12 participants and randomly assign them to either the new technique group or the control group. After the assignment, they discover that, purely by chance, the participants in the new technique group report significantly higher baseline motivation levels than those in the control group. The researchers are concerned that this motivation difference completely invalidates their study's design.
Question: Analyze the researchers' concern in light of the fallibility of random assignment. Explain how the safeguards of the scientific process address their situation, and describe what steps the researchers should understand or take regarding their sample size, statistical analysis, and future work to put this concern into perspective.
Sample answer: While the researchers' concern about a motivation confound is valid, the scientific method has safeguards for this fallibility. First, they should recognize that their small sample size () made this random imbalance more likely, as random assignment works much better in larger samples. Second, when they analyze their data, they must use inferential statistics, which are designed to account for potential random errors and differences between groups. Finally, they should not view a single study as definitive; replicating the experiment with new samples will help detect whether motivation was a true confounding variable that produced misleading results in this initial small-scale test.
Key points:
- Random assignment is fallible and less effective in small samples () compared to large samples.
- Inferential statistics account for the potential random error introduced by chance group differences.
- Replication is necessary to detect if the motivation difference created a confounding variable that led to misleading results.
Rubric: Grading criteria: 1. Explains that the small sample size made the random imbalance in motivation more likely, as random assignment is more effective in large samples. 2. Explains that inferential statistics will account for potential random error when they analyze the results. 3. Explains that replicating the experiment is the ultimate safeguard to detect whether the motivation difference created a confounding variable that produced misleading results.
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Research Methods in Psychology - 4th American Edition @ KPU
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