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Explain the concept of the fallibility of random assignment in experimental design. In your explanation, identify what this fallibility entails and list the three scientific reasons or safeguards that prevent it from being a major concern for researchers.
Question: Explain the concept of the fallibility of random assignment in experimental design. In your explanation, identify what this fallibility entails and list the three scientific reasons or safeguards that prevent it from being a major concern for researchers.
Sample answer: The fallibility of random assignment refers to the fact that it does not guarantee perfect control over all extraneous variables, meaning experimental groups may still differ on certain traits due to chance. However, this is rarely a major concern in research because: 1) random assignment works highly effectively in large samples; 2) inferential statistics mathematically account for potential random error; and 3) any resulting confounding variables are typically detected when the experiment is replicated.
Key points:
- Random assignment does not guarantee perfect control of extraneous variables, allowing chance differences between groups.
- Random assignment is highly effective in large samples.
- Inferential statistics mathematically account for potential random error.
- Replication of the experiment typically detects resulting confounding variables.
Rubric: Grading criteria: 1. Clearly defines that random assignment is fallible because it cannot guarantee perfect control of all extraneous variables due to chance. 2. Identifies large samples as a factor where random assignment is highly effective. 3. Explains that inferential statistics account for potential random error. 4. Notes that replication of the experiment will typically detect any confounding variables caused by chance differences.
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Research Methods in Psychology - 4th American Edition @ KPU
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