# Learn R: Quartiles, Quantiles, and Interquartile Range

In this course, you will learn how to calculate three important descriptive statistics that describe the spread of the data.

Start## Key Concepts

Review core concepts you need to learn to master this subject

Quantiles

Quartiles

Quantiles and Groups

Median in Quantiles

Interquartile Range Definition

Interquartile Range and Outliers

Quantiles

Quantiles

Quantiles are the set of values/points that divides the dataset into groups of equal size. For example, in the figure, there are nine values that splits the dataset. Those nine values are quantiles.

- 2We’ll come back to the music dataset in a bit, but let’s first practice on a small dataset. Let’s begin by finding the second quartile (Q2). Q2 happens to be exactly the median . Half of the dat…
- 4You just learned a commonly used method to calculate the quartiles of a dataset. However, there is another method that is equally accepted that results in different values! Note that there is no …
- 5We were able to find quartiles manually by looking at the dataset and finding the correct division points. But that gets much harder when the dataset starts to get bigger. Luckily, there is a funct…
- 6Great work! You now know how to calculate the quartiles of any dataset by hand and with R. Quartiles are some of the most commonly used descriptive statistics. For example, You might see schools …

- 2Base R has a function named quantile() that will quickly calculate the quantiles of a dataset for you. quantile() takes two parameters. The first is the dataset that you are using. The second para…
- 3In the last exercise, we found a single “quantile” — we split the first 23% of the data away from the remaining 77%. However, quantiles are usually a set of values that split the data into g…
- 4One of the most common quantiles is the 2-quantile. This value splits the data into two groups of equal size. Half the data will be above this value, and half the data will be below it. This is als…
- 5Nice work! Here are some of the major takeaways about quantiles: * Quantiles are values that split a dataset into groups of equal size. * If you have n quantiles, the dataset will be split into n+…

- 1One of the most common statistics to describe a dataset is the
*range*. The range of a dataset is the difference between the maximum and minimum values. While this descriptive statistic is a good s…

## What you'll create

Portfolio projects that showcase your new skills

## How you'll master it

Stress-test your knowledge with quizzes that help commit syntax to memory