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.

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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 this 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.