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Based on the matrix of possible outcomes in null hypothesis testing, diagnose the specific statistical outcome of this study. Explain why it represents this outcome by mapping the scenario to the researcher's decision and the true state of reality.
Case context: A team of researchers conducts a study evaluating whether a new cognitive training program improves memory. After analyzing their data, the researchers formally decide to retain the null hypothesis, concluding that the training program has no effect. However, in reality, the cognitive training program is actually effective at improving memory.
Question: Based on the matrix of possible outcomes in null hypothesis testing, diagnose the specific statistical outcome of this study. Explain why it represents this outcome by mapping the scenario to the researcher's decision and the true state of reality.
Sample answer: The researchers have committed a Type II error. This outcome occurs when researchers decide to retain a null hypothesis that is, in reality, false. In this scenario, the decision was to retain the null hypothesis (concluding no effect), but the true state of reality was that the program was effective (meaning the null hypothesis was actually false).
Key points:
- Diagnoses the outcome as a Type II error.
- Identifies the researcher's decision as retaining the null hypothesis.
- Identifies the actual state of reality as the null hypothesis being false.
Rubric: The response must accurately diagnose the situation as a Type II error and justify this by explaining that the researchers retained the null hypothesis when it was actually false.
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Research Methods in Psychology - 4th American Edition @ KPU
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