In this tutorial, we introduce the two major types of clustering: Flat and Hierarchical. Then we explain the Dendrogram, a visualization of hierarchical clustering.

## What is Flat Clustering?

**Flat clustering** is where the scientist tells the machine how many categories to **cluster** the data into. Hierarchical. Hierarchical **clustering** is where the machine is allowed to decide how many **clusters** to create based on its own algorithms.

## What is Hierarchical Clustering?

**Hierarchical clustering**, also known as **hierarchical cluster** analysis, is an algorithm that groups similar objects into groups called **clusters**. The endpoint is a set of **clusters**, where each **cluster** is distinct from each other **cluster**, and the objects within each **cluster** are broadly similar to each other.

## What is a Dendrogram Graph?

A *dendrogram* is a *diagram* that shows the hierarchical relationship between objects. It is commonly created as an output from hierarchical clustering.