# What are confidence intervals?

##### 1 Answer

A confidence interval is a range of values we are relatively sure our population statistic falls within.

#### Explanation:

A confidence interval is a range of values we are relatively sure our population statistic or parameter falls within. A confidence interval expresses the degree of uncertainty for a sample statistic of a larger population.

The more variation your population has, the larger your confidence interval will be. The larger your sample size, the smaller your confidence interval will be.

To calculate a confidence interval (CI) you need to know the confidence level, the margin of error, and the statistic.

The general formula for a CI is sample statistic ± margin of error (assuming a normal distribution).

You can watch a short video about CI here: