# Lesson 47: Distribution-Free Confidence Intervals for Percentiles

### Introduction

In the previous lesson, we learned how to calculate a sample percentile as a point estimate of a population (or distribution) percentile. Just as it is a good idea to calculate confidence intervals for other population parameters, such as means and variances, it would be a good idea to learn how to calculate a confidence interval for percentiles of a population. That's what we'll work on doing in this lesson. As the title of the lesson suggests, we won't make any assumptions about the distribution of the data, that is, other than it being continuous.

### Objectives

- To learn how to calculate a confidence interval for a median using order statistics.
- To learn how to calculate a confidence interval for any population percentile using order statistics.