Most of our text reading regarding confidence intervals focuses on deriving and calculating their values under a variety of circumstances. More important than that, though, is what we can do with confidence intervals as engineers. Discuss how knowing the confidence interval for some statistical parameter (typically, but not always, the mean value) can affect the decision-making we conduct around that parameter on engineering projects. What might we do differently as a result of having confidence in a range of values rather than feeling we actually know a specific value?