Public Health Quiz #12: Confidence Intervals

1. A clinical trial is conducted to compare the mean systolic blood pressure reduction of a new antihypertensive drug versus placebo. The mean reduction in systolic blood pressure for patients using the drug is found to be 10 mmHg with a 95% confidence interval (CI) of 8 to 12 mmHg. Which of the following is the most accurate interpretation of this confidence interval? 

Question 1 of 5

2. A study assessing the effect of a new diet on cholesterol levels reports a 95% confidence interval for the mean decrease in LDL cholesterol of -20 to -10 mg/dL. Which of the following conclusions can be drawn from this confidence interval? 

Question 2 of 5

3. In a randomized control trial, the 95% confidence interval for the difference in mean recovery time (in days) between a new drug and a standard treatment is reported as -2 to 4 days. How should this confidence interval be interpreted? 

Question 3 of 5

4. A 95% confidence interval for the risk ratio (RR) of developing a side effect from a certain medication compared to a placebo is 0.8 to 1.2. What does this confidence interval suggest about the medication's safety? 

Question 4 of 5

5. Researchers conduct a study to determine the effect of an intervention on systolic blood pressure (SBP). The 95% confidence interval for the mean change in SBP is reported as -3 to 1 mmHg. Which of the following interpretations is correct? 

Question 5 of 5


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