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State the initial step required to analyze data using a dependent-samples -test. In your description, specify how the raw paired scores are transformed, the condition that must be met during this calculation, and what type of statistical test the dependent-samples -test functions as once this step is completed.
Question: State the initial step required to analyze data using a dependent-samples -test. In your description, specify how the raw paired scores are transformed, the condition that must be met during this calculation, and what type of statistical test the dependent-samples -test functions as once this step is completed.
Sample answer: The initial step in a dependent-samples -test is to reduce the two paired scores for each participant into a single value called a difference score, which is calculated by subtracting one score from the other. This subtraction must be applied in a consistent direction for all participants. Once these difference scores are computed, the analysis functions exactly like a one-sample -test performed on these difference scores.
Key points:
- Reduce two paired scores per participant to a single difference score by subtraction.
- The subtraction order must be applied consistently across all participants.
- The choice of subtraction direction is often aligned intuitively with expected outcomes.
- Once difference scores are calculated, the test functions as a one-sample -test.
Rubric: Check that the learner identifies the reduction of paired scores to a single difference score via subtraction, states that the direction of subtraction must be consistent across all participants, and specifies that the analysis then functions as a one-sample -test on the difference scores.
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Research Methods in Psychology - 4th American Edition @ KPU
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State the initial step required to analyze data using a dependent-samples -test. In your description, specify how the raw paired scores are transformed, the condition that must be met during this calculation, and what type of statistical test the dependent-samples -test functions as once this step is completed.
Determine the formula the researcher should use to calculate the difference scores, compute the difference scores for Participant 1 and Participant 2, and explain why the researcher must apply this formula in the exact same direction to all participants in the study.
A research assistant is calculating difference scores for a dependent-samples -test. For the first 10 participants, they subtract Pretest scores from Posttest scores. For the remaining 10 participants, they subtract Posttest scores from Pretest scores because they want all difference scores to be positive. Identify the error in this application and explain how it must be corrected.