1. What is 95% CI For Relative Risk?

The 95% confidence interval for relative risk provides a range of values within which the true relative risk is likely to fall 95% of the time. It gives an estimate of the precision of the relative risk measurement.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( RR \) — Relative Risk (dimensionless)
• \( SE \) — Standard Error of the natural logarithm of RR
• 1.96 — Z-score for 95% confidence interval

Explanation: The formula calculates the confidence interval on the logarithmic scale and then exponentiates to return to the original scale.

3. Importance of Confidence Interval

Details: The confidence interval helps assess the statistical significance of the relative risk. If the interval includes 1.0, the result is not statistically significant at the 5% level.

4. Using the Calculator

Tips: Enter the relative risk value and its standard error. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What does a 95% confidence interval mean?
A: It means that if the study were repeated many times, 95% of the calculated intervals would contain the true population relative risk.

Q2: How is the standard error calculated?
A: The standard error is typically calculated from study data using specific formulas depending on the study design.

Q3: What if my confidence interval includes 1.0?
A: This suggests that the observed effect may be due to chance, as a RR of 1.0 means no difference between groups.

Q4: Can I calculate different confidence levels?
A: Yes, by changing the multiplier (1.96) to the appropriate z-score for your desired confidence level.

Q5: When is this calculation most useful?
A: This is particularly important in epidemiological studies assessing the strength of association between exposure and outcome.