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What is Exploratory Data Analysis(EDA)?
Published: August 11, 2023 | null MIN READ
In this article, we explain what Exploratory Data Analysis is, introduce the three types of EDA and how to do it! Let's learn this complete guide together!
What is Exploratory Data Analysis?
Exploratory Data Analysis (EDA) is a crucial step in the data analysis process, involving the examination and understanding of data before performing any formal modeling or hypothesis testing. EDA techniques were initially developed by American mathematician John Tukey in the 1970s and continue to be widely used methods in the data discovery process. It helps determine how best to manipulate data sources to obtain the desired answers, making it easier for data scientists to uncover patterns, identify anomalies, test hypotheses, or investigate assumptions. It can also assist in determining whether the statistical techniques considered for data analysis are appropriate.
Why is Exploratory Data Analysis Important in Data Science?
The primary purpose of EDA is to aid in examining data before making any assumptions. It enables a thorough understanding of data characteristics, distributions, and potential relationships, while uncovering hidden patterns and anomalies, providing valuable support for subsequent modeling and hypothesis testing. Data scientists can use exploratory analysis to ensure their results are effective and applicable to any desired business outcomes and objectives. EDA also helps answer questions related to standard deviation, categorical variables, and confidence intervals. Once EDA is completed and insights are obtained, its findings can be utilized for more complex data analysis or modeling, including machine learning.
Types of Exploratory Data Analysis
Next, we will discuss three types of Exploratory Data Analysis (EDA).
1. Univariate: In univariate analysis, the focus is on a single variable (or feature) to study its distribution and statistical characteristics.
2. Bivariate: Bivariate EDA involves examining the relationship between two variables, allowing us to observe correlations or associations between them.
3. Multivariate: In multivariate analysis, the exploration typically involves the relationships among three or more variables.
These three types of EDA involve both graphical and non-graphical methods. Graphical methods employ charts, graphs, and other visualizations to study the data, such as boxplots, stem-and-leaf plots, and scatter plots. On the other hand, non-graphical methods use statistical techniques to analyze the data and gain insights into central tendencies, dispersions, skewness, kurtosis, and other characteristics.
1.1 Univariate Non-graphical:
This is the simplest form of data analysis, using statistical techniques and mathematical methods to study the characteristics of a single variable, independent of visualizations. Common univariate non-graphical methods include:
- Descriptive statistics: Summarizing and describing data characteristics by calculating mean, median, variance, standard deviation, etc.
- Percentiles and quartiles: Understanding extreme values and data distribution.
- Skewness and kurtosis: Measuring the symmetry of data distribution and kurtosis.
1.2 Univariate Graphical:
Univariate graphical EDA involves creating charts and graphs to explore individual variables. These visualizations provide an intuitive understanding of data distribution and help identify any outliers. Common types include:
- Histograms: Displaying the frequency distribution of data by dividing it into intervals and plotting bar-like shapes.
- Boxplots: Presenting the five-number summary (minimum, first quartile, median, third quartile, maximum) to identify outliers and data dispersion.
- Kernel density estimation plots: Estimating the probability density function with a smooth curve to show data distribution.
- Bar charts: Representing the frequency or proportion of categorical data using bars.
2.1 Multivariate Non-graphical:
Multivariate data involves multiple variables. Multivariate non-graphical EDA techniques often show the relationship between two or more variables through regression analysis or cross-tabulation. Common analysis methods include:
- Correlation analysis: Measuring the linear correlation between two numerical variables.
- Regression analysis: Modeling and predicting the relationship between one or more dependent variables and one or more independent variables.
- Principal Component Analysis (PCA): Reducing dimensionality and discovering major components among multiple correlated variables.
2.2 Multivariate Graphical:
Multivariate graphical EDA uses graphs to display relationships between two or more groups of data. Common graphical types include:
- Scatter plots: Representing the relationship between two numerical variables, with each data point representing an observation.
- Heatmaps: Encoding the association between two categorical variables using color.
- Bubble charts: Displaying multiple circles in a 2D plot, often used to show the relationship between three numerical variables.
These analysis methods help us gain a deeper understanding of the complex relationships and patterns among multiple variables, providing more comprehensive and insightful insights for data analysis and decision-making. It is worth noting that multivariate graphical and non-graphical analyses are often used in combination to reveal the complexity and relationships within the data.
Exploratory Data Analysis Steps
Exploratory Data Analysis (EDA) is a pivotal step in the data analysis process, involving the examination and comprehension of data before any formal modeling or hypothesis testing is performed. The following are typical steps involved in conducting EDA:
1. Data Collection
In today's world, data is generated in vast volumes and diverse forms, touching nearly every aspect of human life—from healthcare and sports to manufacturing and tourism. The ability to collect and utilize data from various sources, including MPP databases and ERP systems like mySAP, has become essential for unlocking its full potential. Whether gathering data from databases, files, APIs, or through web scraping, it’s crucial to ensure that the data is structured and well-organized for effective analysis.
FineBI, developed by FanRuan, is designed to overcome the complexities associated with integrating data from multiple business platforms, diverse databases, and various data interfaces within enterprises. FineBI offers robust data access capabilities, enabling the seamless integration of different data sources into a unified platform for comprehensive analysis. Whether dealing with databases, text files, or programmatic data sources, FineBI allows organizations to bring together disparate data into a cohesive system, facilitating deeper insights and more informed decision-making.
With FineBI, businesses can navigate the challenges of data diversity and complexity, transforming raw data into strategic assets that drive growth and innovation.
2. Data Cleaning
The next step involves cleaning the dataset. This process eliminates missing values, duplicates, anomalies, and inconsistencies, ensuring that the data contains only those values that are relevant and significant from the desired perspective. Data cleaning ensures high-quality data devoid of errors that could affect analysis.
Here we utilize FineBI's data cleansing feature to examine whether fields contain specific strings and group them accordingly. For example, if a field contains 'A', then display 'A'; if it contains 'B', then display 'B'. For example, "Province or City" containing "Province" is displayed as 1, as shown in the following figure.
Our approach involves using the Find function to ascertain the presence of the value within the field and employing the IF function for conditional determination. The specific steps are as follows:
Use Demo Data"Regional Data Analysis". Create the Self-Service dataset and select all the data, as shown below.
Then, Add a new column. New return value column "Test", if the field contains "Province", it returns a 1, then find ("Province", Province or City) in the IF function logical value of true, for conditional judgment, contains the display for "1", otherwise display for "0".
This way, we have achieved the functionality of checking fields and grouping them during data cleansing. Of course, FineBI has many more features awaiting your exploration!
3. Variable Identification
At the outset of the analysis, identify all variables and understand them logically. These continuously changing data represent distinct information. Begin by checking data size, data types, and the first few rows to gain a basic understanding. Then, attempt to comprehend the correlations between different variables, revealing how specific variables are interrelated. This step is crucial for any anticipated analysis outcomes.
4. Summary Statistics and Analysis
In EDA, selecting the correct statistical methods and conducting summary statistics is crucial. After identifying key variables, consider data types and use measures like mean and frequency to understand data distribution and central tendencies. If analyzing correlations, leverage a correlation coefficient matrix to detect variable associations.
5. Data Visualization and Analysis
Then, we need to apply visualization techniques to data, creating visual representations using various plots and charts. Common plots include histograms, box plots, scatter plots, bar charts, and more. Data analysts should possess strong analytical skills, expertise in analysis techniques, and the ability to accurately interpret visualized results, and apply them to specific domains.
Here, we strongly recommend trying FineBI, which offers over 50 built-in chart types, covering basic and advanced charts, and supporting various descriptive statistics and analyses. It also boasts dynamic effects and powerful interactive experiences, providing an exceptional data analysis experience.
Remember, EDA is an iterative process. As new insights are revealed or new questions arise, you may revisit certain steps. The primary goal is to deeply understand the data and guide subsequent steps in data analysis or modeling processes.
Exploratory Data Analysis Tools
Exploratory Data Analysis (EDA) involves using various tools to effectively visualize and analyze data. Here are some popular tools commonly used for EDA:
1. Python Libraries:
- Pandas: Provides data manipulation capabilities such as reading, cleaning, and transforming data.
- NumPy: Offers numerical computation functions for handling arrays and matrices.
- Matplotlib: Widely used plotting library for creating static, interactive, and animated visualizations.
- Seaborn: Built on top of Matplotlib, it provides a higher-level interface for creating attractive statistical graphics.
2. R Language:
- RStudio: An integrated development environment (IDE) for the R programming language.
- ggplot2: A popular package for creating elegant and expressive data visualizations.
- dplyr: Provides a set of functions for data manipulation tasks such as filtering, summarizing, and joining.
- reshape2: Allows data reshaping and transformation to meet specific analytical requirements.
3. FineBI:
FineBI is a powerful data analysis tool that enables interactive and intuitive exploration of data through drag-and-drop functionality. It is commonly used for creating dashboards, analytic reports, and conducting Exploratory Data Analysis (EDA).
- FineBI's user-friendly interface makes it easy to connect to various data sources and transform raw data into meaningful insights.
- The tool offers a variety of visualization options, including charts, graphs, and other visual elements, and helps you explore relationships between variables, identify outliers, and visualize data distributions.
- Use FineBI's features to design an interactive dashboard, combining multiple visualizations and analysis components into a single view. You can create dynamic filters and parameters to allow real-time exploration and interaction with the data.
- Leverage FineBI to perform statistical tests, hypothesis testing, and other advanced analyses to validate assumptions and draw meaningful conclusions from your data.
By using FineBI for Exploratory Data Analysis, you can efficiently visualize, explore, and understand your data, uncover hidden patterns and relationships, and provide insights for further analysis and decision-making.
4. Microsoft Excel:
While Excel may not be as specialized as other tools, it has broad accessibility and is often used for basic EDA tasks such as data cleaning, simple visualization, and summary statistics.
The choice of tools depends on factors such as data size, complexity, and specific analysis requirements. Python and R are particularly popular among data scientists due to their rich libraries and flexibility, while FineBI finds widespread use in business environments for its user-friendly interface and interactive capabilities. Regardless of the tool used, the primary goal is to extract insights from data and effectively communicate results.
Summary
In summary, Exploratory Data Analysis (EDA) is an essential phase within the journey of data analysis, offering valuable insights and a deeper understanding of your datasets. By uncovering hidden patterns, detecting anomalies, and revealing relationships, EDA acts as a potent precursor to informed decision-making and insightful analytics.
To embark on your EDA journey most efficiently and effortlessly, consider harnessing the capabilities of FineBI – a robust and user-friendly data analysis tool. With its intuitive drag-and-drop interface, FineBI empowers you to seamlessly explore and interact with your data, enabling the creation of dynamic dashboards and reports that eloquently convey your discoveries.
Don't just analyze your data; let FineBI transform it into a visual masterpiece, empowering you to delve into the intricacies of your dataset like never before. Embrace the dynamic interplay between insightful exploration and cutting-edge technology by embracing FineBI for your EDA pursuits. Begin your journey now and unleash the untapped potential hidden within your data in unprecedented ways.
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