# Confidence Interval, Plain and Simple

A confidence interval is a **range of values that likely contains the true answer** you're trying to estimate.

## An Example

Imagine you want to know the average height of all adults in your country. You can't measure everyone, so you measure a sample of 1,000 people. Your sample average might be 5'7" (170 cm).

But you know your sample isn't perfect—it's just one group out of millions. So instead of saying "the average is exactly 170 cm," you say:

> "The average is probably somewhere between 168 cm and 