Confidence Intervals

Every election night the screen reads "Candidate X: 52%, ±3%." Nobody claims they know exactly 52%. They draw a fence — 49% to 55% — and say the true number almost certainly lives inside it. That fence is a confidence interval, and the ±3% is its margin of error. It's honesty in math form: here's my best guess, and here's how much I could be off.