Confidence Intervals

A confidence interval is a range of values that's likely to have the true value of a population parameter based on sample data. Let's say you surveyed a sample of high school teachers and found their average salary was $75,000. Since that's just a sample, you can't say for sure it reflects all teachers, but we can say:

"We're 95% confident that the real average salary for all teachers falls between $72,000 and $78,000."

The confidence interval is between $72,000 and $78,000. It gives us a buffer to account for uncertainty in our estimate.