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Explain why the researcher's approach is incorrect for analyzing this experiment. Detail what steps they should have taken instead using descriptive statistics, and how they should use those statistics to draw a conclusion about the conditions.
Case context: A researcher investigates whether a new learning app improves exam performance compared to a standard textbook. They assign students to use the learning app and students to read the textbook, measuring exam scores quantitatively. To analyze the results, the researcher calculates a single, combined mean and standard deviation across all students.
Question: Explain why the researcher's approach is incorrect for analyzing this experiment. Detail what steps they should have taken instead using descriptive statistics, and how they should use those statistics to draw a conclusion about the conditions.
Sample answer: The researcher's approach is incorrect because calculating a single combined mean fails to show whether the independent variable manipulation had an effect. Instead, the researcher should have calculated the mean and standard deviation for the learning app group and the textbook group separately. They should then compare the separate means from each experimental condition to see if they differ from one another.
Key points:
- Explain that pooling all scores prevents evaluating the differences between conditions.
- State that means and standard deviations must be calculated separately for each experimental condition.
- Describe comparing the separate condition means to see if they differ.
Rubric: Full credit is awarded if the student: 1. Explains that a combined mean does not allow for comparison between the experimental groups. 2. Identifies that means and standard deviations must be calculated separately for each experimental condition (the app group and the textbook group). 3. Explains that the separate means must be compared to see if they differ from one another.
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Research Methods in Psychology - 4th American Edition @ KPU
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