An analysis of confidence interval precision is analogous to a traditional power analysis, with *CI Half-Width* taking the place of effect size and *Prob(Width)* taking the place of power. The *CI Half-Width* is the margin of error associated with the confidence interval, the distance between the point estimate and an endpoint.
The *Prob(Width)* is the probability of obtaining a confidence interval with *at most* a target half-width.

The POWER procedure performs confidence interval precision analyses for t-based confidence intervals for one-sample, paired, and two-sample designs, and for several varieties of confidence intervals for a binomial proportion.