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Based on the causes of these three outliers, explain the appropriate management strategy the researchers should apply to each participant's response. In addition, explain what the researchers should do with the data from any excluded participants and how they should report their decisions in their research paper.

Case context: A cognitive psychology lab is analyzing reaction time data from a computer-based attention task. During data cleaning, they encounter three problematic data points: 1. Participant A has a reaction time of 9.00 milliseconds, which is physically impossible and is traced back to a software logging typo. 2. Participant B has a reaction time of 120,000 milliseconds (2 minutes) because they walked away from the computer mid-trial to answer a phone call, showing a clear lack of task effort. 3. Participant C has a reaction time of 950 milliseconds, which is extremely slow compared to the sample average of 300 milliseconds, but the logs confirm Participant C was fully focused and this is a valid, accurate reflection of their natural performance.

Question: Based on the causes of these three outliers, explain the appropriate management strategy the researchers should apply to each participant's response. In addition, explain what the researchers should do with the data from any excluded participants and how they should report their decisions in their research paper.

Sample answer: For Participant A, the researchers should correct the software logging typo. For Participant B, since the outlier stems from a lack of effort, the response can be excluded using consistent criteria. For Participant C, because the response is a valid extreme score, the researchers should keep the data but manage it by using robust statistics (such as the median) or by running their analyses both with and without Participant C's data. The data for Participant B must not be permanently deleted but set aside for future review. In the final paper, the researchers must report that one response (Participant B) was excluded and state the specific criterion used (lack of effort due to task interruption).

Key points:

  • Correct Participant A's data entry/logging error.
  • Exclude Participant B's response using consistent criteria due to lack of effort.
  • Retain Participant C's valid extreme response and manage it using robust statistics (e.g., median) or dual analyses.
  • Set aside Participant B's excluded data for potential future review instead of permanently deleting it.
  • Report the number of exclusions (1 response/participant) and the specific criteria used (lack of effort/trial interruption) in the results.

Rubric: The student must correctly map the handling strategy to each outlier's cause (correct Participant A's error, exclude Participant B's response using consistent criteria, and use robust statistics or dual analyses for Participant C's valid extreme response). The student must also specify that excluded data (Participant B) is set aside rather than deleted, and that the final paper must report the number of exclusions (1 participant) and the specific criteria used.

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Updated 2026-05-27

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Research Methods in Psychology - 4th American Edition @ KPU

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