Solutions to Exercise 17 Questions

EXERCISE 17 Questions to Be Graded
Follow your instructor’s directions to submit your answers to the following questions for grading. Your instructor may ask you to write your answers below and submit them as a hard copy for grading. Alternatively, your instructor may ask you to use the space below for notes and submit your answers online at http://evolve.elsevier.com/Grove/Statistics/ under “Questions to Be Graded.”

1. What are the assumptions for conducting a paired or dependent samples t-test in a study? Which of these assumptions do you think were met by the Lindseth et al. (2014) study?

2. In the introduction, Lindseth et al. (2014) described a “2-week washout between diets.” What does this mean? Why is this important?

3. What is the paired t-test value for mood (irritability) between the participants’ consumption of high- versus low-aspartame diets? Is this result statistically significant? Provide a rationale for your answer.

4. State the null hypothesis for mood (irritability) that was tested in this study. Was this hypothesis accepted or rejected? Provide a rationale for your answer.
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5. Which t value in Table 2 represents the greatest relative or standardized difference between the high- and low-aspartame diets? Is this t value statistically significant? Provide a rationale for your answer.

6. Discuss why the larger t values are more likely to be statistically significant.

7. Discuss the meaning of the results regarding depression for this study. What is the clinical importance of this result?

8. What is the smallest, paired t-test value in Table 2? Why do you think the smaller t values are not statistically significant?

9. Discuss the clinical importance of these study results about the consumption of aspartame. Document your answer with a relevant source.

10. Are these study findings related to the consumption of high- and low-aspartame diets ready for implementation in practice? Provide a rationale for your answer.