Question

Point estimate (relative risk) MUST be within the _________.

a) 99% confidence interval; 1-99
b) 90% confidence interval; 5-95
c) 95% confidence interval; 2.5-97.5
d) 80% confidence interval; 10-90

Answer 1

The correct answer is c) 95% confidence interval; 2.5-97.5, because a 95% confidence interval has a 2.5% chance of the true value falling below the lower bound and a 2.5% chance above the upper bound, leaving the point estimate within these percentiles.

Step-by-step explanation:

The question asks where the point estimate (relative risk) must lie within different confidence intervals. The correct answer is c) 95% confidence interval; 2.5-97.5. This is because a 95% confidence interval is constructed such that there is a 2.5% chance the true value is below the lower bound and a 2.5% chance it is above the upper bound, leaving 95% in the middle where the point estimate should be. By comparison, a 99% confidence interval would leave 0.5% on each end, and a 90% confidence interval would leave 5% on each end. Thus, the point estimate does indeed fall within the 95% confidence interval, specifically between the 2.5th and 97.5th percentile of the normal distribution.