Confidence intervals are really important when we're trying to guess about a whole group of things based on a smaller group.

They give us a range of values where we think the true number might be.

Here's an example to help you understand:

• If you figure out a 95% confidence interval for an average from a sample, you're basically saying there's a 95% chance that this range includes the true average for the entire group.

• To put it simply, if the sample average is $\bar{x}$ and we have something called the standard error, which we write as $SE$, we can show this range like this: $\bar{x} \pm Z \cdot SE$.

Using confidence intervals helps data scientists make smart choices because they can trust the numbers they're looking at.