Fig. 1

Probability density function of the difference between two sample means. The point estimate is the most likely value of the parameter of interest across the CI. A confidence interval (CI) is a range of values used to estimate a population parameter and is associated with a specific confidence. With a CI of 95% confidence, there is a 95% probability that any given CI will contain the true population parameter and a 5% chance that it won’t (two tails of 2.5%)