---
title: "Visualizing Z variable using color"
slug: "coloring-by-categorical-z"
updated: 2025-09-11T13:01:43Z
published: 2025-09-11T13:01:43Z
canonical: "userguide.dataclassroom.com/coloring-by-categorical-z"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://userguide.dataclassroom.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Visualizing Z variable using color

*Before you play with color, pick your z-variable:*

![](https://cdn.document360.io/62f8f41e-e041-42c4-b9bc-8ae1eb45d064/Images/Documentation/z.png)

## **Using Color to Visualize the z variable:**

If you add a **categorical Z variable** to a **dot plot, histogram** or a **bar chart** it will **color** the data points according to the category. This can help you see visually if there is a correlation between the Z variable and the others.

### Dot plot

Here is an example of the same graph, but two different z-variable types:

- Categorical -  **Character Gender** has two values, **F** and **M** and is represented by two distinct colors
- Numeric - **age difference** creates a scale of color to represent the numerical values.

![](https://cdn.document360.io/62f8f41e-e041-42c4-b9bc-8ae1eb45d064/Images/Documentation/Untitled%20drawing-22.png)

### Histogram

In the histogram case (numerical X, categorical Z) the histogram will be divided up into colored bars according to the Z variable:

![](https://cdn.document360.io/62f8f41e-e041-42c4-b9bc-8ae1eb45d064/Images/Documentation/image-1617972723014.png)

This is actually grouping by Z

As the histogram has no other way to show the Z variable, this is actually a case of grouping by Z and will also mean that separate descriptive stats can be shown for each group. See [this article about grouping by Z](/v1/docs/grouping-by-a-z-variable).

### Frequency Plot

For a bar frequency plot (categorical X, categorical Z) it again splits the bars by the Z variable:

![](https://cdn.document360.io/62f8f41e-e041-42c4-b9bc-8ae1eb45d064/Images/Documentation/image-1617972847794.png)

### Customizing colors

In the examples above, the colors have been chosen from an automatic scale that ensures a good contrast. However, you might want to select the colors yourself. This can be done in the **Values** dialog for the column (located within the column header):

![](https://cdn.document360.io/62f8f41e-e041-42c4-b9bc-8ae1eb45d064/Images/Documentation/image-1756062309234.png)

This opens the Values dialog, that allows to you set colors (and labels) for each categorical value:

### See also

Setting a DataMoji for each categorical value - [see here](/v1/docs/fun-with-datamojis)

[Grouping data by a Z variable](/v1/docs/grouping-by-a-z-variable)