## Data Analysis and Visualization with Python Seaborn

Data analysis is a crucial process that provides insights into different aspects of our daily lives, such as business trends, healthcare research, and environmental studies. As data sets become more complex, it becomes increasingly challenging to extract useful information from them.

One way to cope with this problem is through data visualization. Visualization is a powerful tool that allows us to present complex data sets in a more accessible way.

This article will introduce you to Python Seaborn, a popular data visualization library used extensively by data scientists.

### Purpose of Data Visualization

The purpose of data visualization is to transform large amounts of data into visual representations that allow us to better understand the information. Data visualization affords us the ability to identify trends, patterns, and relationships that might not be apparent in their raw form.

With the aid of visualization, data analysis becomes more manageable and can be understood by a broader audience. Therefore, data visualization is one of the most critical steps in data analysis.

### Differences between Seaborn and Matplotlib

Seaborn and Matplotlib are both data visualization Python libraries. Matplotlib is a low-level library, primarily used to create basic visualizations.

On the other hand, Seaborn is a high-level library intended to provide better illustrations than Matplotlib. Seaborn is built on top of Matplotlib, which means it leverages the full power of Matplotlib while providing different visualizations that are not available in Matplotlib.

### Some of the differences between Seaborn and Matplotlib are:

- Seaborn has a higher-level API available for more straightforward data visualization.
- Seaborn provides an extensive range of pre-built visualizations, specifically those that are difficult to implement with Matplotlib.
- Seaborn is ideal for generating better-looking plots and has default color palettes and themes.

### Installation of Seaborn

To use Python Seaborn, you must first install it. The simplest method of doing so is with the python package manager pip.

Open a command prompt or terminal window on your computer, and type the following:

`pip install seaborn`

### Required Modules for Seaborn

Seaborn is designed to work seamlessly with other scientific computing libraries such as NumPy, Pandas, and SciPy. Thus Seaborn has dependencies on these libraries. Therefore, it’s essential to ensure that these libraries are installed on your system.

### Below are the modules needed for Seaborn:

- Matplotlib – Matplotlib is a plotting library that provides an API for creating plots and visualizations in Python.
- NumPy – NumPy is a fundamental library used for processing numerical arrays and matrices.
- Pandas – Pandas is a data analysis library that provides easy-to-use data structures and data analysis tools.
- SciPy – SciPy is an open-source scientific computing library that contains tools for optimization, integration, and linear algebra.

### Data Files Used Throughout the Tutorial

To practice using Seaborn, we need datasets. Through Seaborn, we can import different datasets, including CSV files, from various sources.

### Conclusion

Python Seaborn is a widely used library for data visualization in Python. It provides a higher-level API than Matplotlib, allowing for easier creation of visualizations.

These visualizations can ultimately provide insight into complex data sets and make it easier for non-technical audiences to understand them. Installing Python Seaborn can be straightforward, and it has dependencies on other fundamental scientific computing libraries.

Through Seaborn, we can import different datasets, including CSV files, and use them to practice data visualization.

## Python Seaborn for Statistical Analysis

Statistical analysis is an essential component of data visualization. The aim of statistical analysis is to provide a more in-depth understanding of the data set by analyzing patterns and relationships that might exist between variables.

There are different methods to conduct statistical analysis on data sets, and Python Seaborn provides various functions to help accomplish this task.

### Importance of Statistical Analysis in Data Visualization

The role of data visualization is to provide a visual representation of the data set, making it easier for analysts to identify patterns and relationships. However, the output of data visualization can be misleading if it’s not analyzed correctly.

Statistical analysis provides a method of interpreting the visual output produced by data visualization. In this way, analysts can draw more accurate conclusions from the visualization output.

### Functions for Statistical Analysis in Seaborn

Seaborn provides different functions that facilitate statistical analysis in data visualization. Some of the commonly used functions for statistical analysis in Seaborn are:

`scatterplot()`

: A scatterplot can be used to represent numerical data.`lineplot()`

: A line plot is another commonly used type of plot for numeric data visualization. Its primary objective is to depict trends or patterns that exist in the data set, such as an increasing or decreasing trend over time.

### Categorical Scatter Plot

Categorical data refers to data that is typically divided into clear and distinct groups. These groups are often represented by labels, such as country or gender.

Categorical data is different from numerical data, which can be continuous rather than discrete. In data visualization, it is common to use scatter plots to display the relationship between two continuous variables.

However, for categorical data, it may be necessary to display more than one variable to get a deeper understanding of the data. Categorical scatter plots are used to display the relationship between two categorical variables.

### Categorical Data

Categorical data is a type of data that can be divided into discrete groups or categories.

Examples of categorical data include gender (male or female), occupation (engineer or teacher), and race/ethnicity (white, black, Hispanic, etc.). Categorical data is different from numerical data in that it is not continuous, meaning the values cannot be measured along a numerical scale.

### Different methods to visualize Categorical Data in Seaborn

Seaborn provides different methods of visualizing categorical data. Some commonly used ones are:

`catplot()`

: The`catplot()`

function in Seaborn is used to display relationships between a numerical variable and one or more categorical variables.`stripplot()`

: The strip plot function is used to display the distribution of a single categorical variable along a numerical axis. It is accomplished by placing individual data points along the axis and stacking them.`swarmplot()`

: The`swarmplot()`

function is also used to display the distribution of a single categorical variable along a numerical axis.

### Conclusion

Python Seaborn is a powerful tool for statistical analysis in data visualization. Its different functions make it easier for analysts to identify patterns and trends in complex data sets.

Categorical data can also be displayed in different ways using functions like `catplot()`

, `stripplot()`

, and `swarmplot()`

to make it more accessible for data analysts. Statistical analysis is an essential part of the data visualization process, and Seaborn can be used to facilitate a deeper understanding of data sets for improved decision-making.

## Categorical Distribution Plots

Data visualization plays a crucial role in identifying patterns and trends in a data set. Apart from scatter plots, line plots, and bar plots, Seaborn provides different visualization techniques to represent categorical data in the form of distribution plots.

### Categorical Distribution Data

Categorical distribution data is a type of data in which the possible values are limited to a set of categories.

It is different from numerical data, which can be continuous, meaning a value can take on any value along a numerical scale. In categorical distribution data, each value can only take on one of the possible categories.

Examples of categorical distribution data include the type of colors which can be primary or secondary, different types of fruits, or different species.

### Functions to represent Categorical Distribution Data

Seaborn provides different visualization techniques to represent categorical distribution data. Some of them are:

`violinplot()`

: This function is used to visualize the distribution of data across each category.`boxplot()`

: The`boxplot`

function is useful for visualizing categorical distribution data. It displays a summary of the data distribution.`boxenplot()`

: The`boxenplot`

function is similar to the`boxplot`

function, but it is better suited for visualizing the distribution of categorical data that is heavy-tailed or has more outliers.

### Categorical Estimate Plots

Another way to visualize categorical data is to use categorical estimate plots. These plots use an estimator function to calculate an estimate of the central tendency of the data.

### Categorical Estimate Data

Categorical estimate data is a type of data used to represent qualitative information.

It helps to get an idea about the size of the different categories and their statistical distribution. One of the fundamental characteristics of categorical estimate data is that it doesn’t have a numerical scale and is based on non-numerical quantities.

### Functions to estimate Categorical Data

Seaborn provides different visualization techniques to estimate categorical data. Some commonly used ones are:

`countplot()`

: The`countplot()`

function can be used to display the frequency of observations in each category.`barplot()`

: The`barplot()`

function is useful when you need to display the mean of a numerical variable in each category.`pointplot()`

: The`pointplot()`

function is similar to the`barplot()`

function but instead uses the point estimate to plot the data.

### Conclusion

Different visualization techniques can represent categorical data. Seaborn provides functions to visualize distribution and estimate plots, which helps in identifying patterns and trends in categorical data.

Using the right visualization technique for categorical data helps to deliver proper insights to data analysts to support decision-making.

## Customized Styles and Themes in Seaborn

Python Seaborn allows for the customization of plots beyond the default settings. This article will cover the different styles and themes available in Seaborn and how to implement them.

It will also delve into multi-plot grids to represent large data sets with categorical values.

### Pre-defined Themes and Styles in Seaborn

Seaborn provides several predefined themes and styles that are perfect for specific visualization needs. These themes and styles are available through the Seaborn package and can be easily implemented.

The currently available pre-defined styles/themes in Seaborn are:

- darkgrid
- whitegrid
- dark
- white
- ticks

Each pre-defined theme and style has unique features and properties, which can be improved to suit specific visualization needs.

### Implementation of Themes in Seaborn

To implement themes in Seaborn, we can use the `set_style()`

function. This function changes the style of all the subsequent Seaborn visualizations.

The common styles that are implemented using the `set_style()`

command include:

`darkgrid`

: This style has a dark black background grid and white grid lines. It is suitable for plots that require a dramatic look.`whitegrid`

: This style has a white background grid and black grid lines. It is perfect for minimalistic graphs that need to convey simplicity.`dark`

: This style has a black background with white font. It is suitable for visualizations that require contrast and sophistication.`white`

: This style has a white background with black font. It is perfect for a traditional look.`ticks`

: This style has only tick marks on the axis, making it ideal for simple visualizations.

### Multi-plot Grids in Seaborn

Seaborn provides different visualization techniques that allow for the representation of large data sets with categorical values. If the data set is significant with multiple categories, it can be challenging to display the data in one plot.

This is where multi-plot grids come in.

### Representation of Large Data Sets with Categorical Values

To represent large data sets with categorical values, Seaborn provides multi-plot grids. These grids enable visualization of sub-sets of data in a single plot.

It’s a powerful tool that allows data analysts to efficiently visualize large data sets.

### FacetGrid Class for Multiple Plots

The `FacetGrid`

class in Seaborn allows for multiple plots or facets to be created. It takes in a series of arguments, including the data set, the categories to be displayed, and the name of the columns or rows to be used for slicing the data.

Then, using the `FacetGrid`

object, a specified plot type (e.g., `barplot`

, `boxplot`

, `scatterplot`

) along with the categories are displayed in a single plot. For example, if we want to plot a bar chart of the survival rate of passengers based on their sex and class on the Titanic, we can use the following command:

`g = sns.FacetGrid(titanic_df, row='sex', col='class')`

`g.map(sns.barplot, 'survived', y='embarked')`

This creates a grid of plots with two rows (male and female) and three columns (first, second, and third class), with the bar chart for the survival rate of passengers.

### Conclusion

Seaborn provides different styles/themes and multi-plot grids to customize and represent large data sets with categorical values. The `set_style()`

function allows for changing the style of all subsequent Seaborn visualizations.

Mult-plot grids allow for visualization of sub-sets of data in a single plot, and the `FacetGrid`

class makes it possible to create multiple plots or facets. These features allow data analysts to efficiently visualize large and complex data sets and draw insights from the data.

## Plotting Univariate and Bivariate Distributions with Seaborn

Data visualization is a critical component of data analysis, and Seaborn provides a powerful toolset for this purpose. Among Seaborn’s different visualization techniques, one of the most useful is the ability to plot and represent univariate and bivariate distributions.

### Univariate Distribution

Univariate distribution is a statistical concept that describes a distribution of a random variable in terms of a single attribute or variable.

It measures the frequency of each unique outcome of a random variable in a sample set. An example of a univariate distribution would be a histogram of the heights of individuals in a population.

### distplot() Function to Represent Univariate Distributions

The Seaborn `distplot()`

function is used to plot a univariate distribution of an array of observations. It combines a histogram of the data set with a kernel density estimate (KDE).The resulting plot provides a visual representation of the data’s distribution, including the spread, skewness, and kurt