## Statistical Study Example

Read the "Research Letter" section of this recent edition of the Journal of the American Medical Association, and answer the following questions.

Research Letter (pdf file 60K)

In Table 2, there is a row for the peak heart rate of the participants.

1. Given the information in the table, compare the range of the peak heart rate in beats per minute for participants who drank oxygenated water versus those who drank nonoxygenated water.

2. How was the mean difference calculated?

3. Why is important that the 95% CI for the mean difference in this row (and, in fact, all rows in this table) includes the value of zero?

4. Explain what the P value means.

5. Given the information in the tables, which water would you drink before doing some heavy exercise?

6. How would your answer to the previous question change if the only information you had was the final paragraph of this research letter?

Bonus question: What data were used to calculate the 95% CI for the mean difference?