Name: _______________________________

**Exercise 16**** –****Understanding Independent Samples ***t***-Test**

1. What do degrees of freedom ( *df *) mean? Canbulat et al. (2015) did not provide the *df *s in their study. Why is it important to know the *df *for a *t *ratio? Using the *df *formula, calculate the *df *for this study.

2. What are the means and standard deviations ( *SD *s) for age for the Buzzy intervention and control groups? What statistical analysis is conducted to determine the difference in means for age for the two groups? Was this an appropriate analysis technique? Provide a rationale for your answer.

3. What are the *t *value and *p *value for age? What do these results mean?

4. What are the assumptions for conducting the independent samples *t *-test?

5. Are the groups in this study independent or dependent? Provide a rationale for your answer.

6. What is the null hypothesis for procedural self-reported pain measured with the Wong Baker

Faces Scale (WBFS) for the two groups? Was this null hypothesis accepted or rejected in this

study? Provide a rationale for your answer.

7. Should a Bonferroni procedure be conducted in this study? Provide a rationale for your answer.

8. What variable has a result of *t *= − 6.135, *p *= 0.000? What does the result mean?

9. In your opinion, is it an expected or unexpected finding that both *t *values on Table 2 were found to be statistically significant. Provide a rationale for your answer.

10. Describe one potential clinical benefit for pediatric patients to receive the Buzzy intervention

that combined cold and vibration during IV insertion.

**Exercise 17****Understanding Paired or Dependent Samples ***t***-Test**

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 signifi cant? 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.

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.