WEEK 2 ARTICLE EXPLORATORY DATA ANALYSIS (ESD) USING DATA VISUALIZATION TECHNIQUE
Published: 2023-10-13 14:14:56

Exploratory Data Analysis is a scientific approach to understanding the storage of data also an iterative, interactive and preliminary phase of a Data Science project that allows the extraction of important information from the data to identify patterns/anomalies, identify trends, relationships within dataset, improve quality of data, generate hypotheses that need to addressed and summarizes statistics to drive meaningful insights for important business decisions. It is a significant step before statistical modelling or machine learning to ensure data is real and there are no errors as it examines and understands data, find relationship between variables in a dataset before diving into complex analysis. 

Different data types (numerical, categorical and text) can be analyzed using EDA. It is typically done before data analysis to identify and correct the errors in data, visualize the key attributes of the data.

WHY EXPLORATORY DATA ANALYSIS (EDA)?
Raw data is usually skewed (may be characterized by outliers or too many missing values). A model built on such data results gives optimal performance with the implications of generating accurate models on wrong data, not creating the right types of variables in data preparation and using resources inefficiently.

Exploratory Data Analysis Steps 
1. Data Cleaning: handling missing values, removing outliers and ensuring data quality.
2. Data Exploration: examining summary statistics, visualizing data distributions, and identifying patterns or relationships.
3. Feature Engineering: transforming variables, creating new features, or selecting relevant variables for analysis.
4. Data Visualization: presenting insights through plots, charts, and graphs to communicate findings effectively.

TYPES OF Exploratory Data Analysis Steps
1. UNIVARIATE ANALYSIS
Univariate analysis focuses on understanding the distribution and characteristics of individual variables within a dataset. It identify outliers, assess the distribution of data, and make informed decisions about data preprocessing.  The techniques for univariate analysis include:
1a)	Bar Charts are suitable for visualizing categorical or discrete data. 

1b). Histograms
Histograms are graphical representations of the frequency distribution of a single variable which identify patterns such as skewness, central tendencies and outliers.
1c). Box Plots
Box plots provide a visual summary of the distribution of a variable for detecting outliers, understanding the spread and symmetry of data, and identifying dominant categories.
1d). Density Plots
Density plots show the probability density of a continuous variable. They are useful for visualizing the underlying distribution of data, including modes and areas of high concentration example the Kernel density estimation (KDE).
2. Bivariate Analysis
Bivariate analysis explores the relationships between two variables in a dataset. It helps uncover patterns, dependencies, and correlations between two variables and understand how changes in one variable relate to changes in another. The techniques for bivariate analysis include:
2a). Scatter Plots
Scatter plots display the relationship between two continuous variables by plotting each data point as a point on a two-dimensional grid and identify patterns, clusters and trends in data. 
2b). Correlation Heatmaps
Correlation heatmaps visualize the correlation coefficients between pairs of continuous variables and aids in understanding the strength and direction of linear relationships between variables. 
2c). Pair Plots
Pair display scatter plots for all possible pairs of continuous variables in a dataset and provides a comprehensive view of the relationships between variables to explore multiple variables simultaneously.
3. Multivariate Analysis
Explores more than two variables simultaneously to gain a holistic understanding of the data and uncover intricate patterns that may not be apparent in univariate or bivariate analyses. It uncovers complex relationships and interactions between multiple variables in a dataset. techniques for multivariate analysis are correlation heatmaps and pair plot, others Include:
3a). 3D Scatter Plots
3D scatter plots extend the concept of scatter plots to three continuous variables. They provide insights into how three variables are related in three-dimensional space, making it possible to visualize complex interactions.
3b). Parallel Coordinates
Parallel coordinate plots are useful for visualizing high-dimensional data. They display each data point as a line that passes through multiple axes to identify clusters and relationships in high-dimensional data.
3c. Principal Component Analysis (PCA)
It simplifies complex datasets and aids in identifying dominant patterns and relationships.

Exploratory Data Analysis using Data Visualization Technique
This is a process of describing the data using statistical and visualization techniques that focus on important aspects of data for further analysis without making any assumptions on its contents. It adopts multiple techniques like visualization, summary statistics and data transformation to abstract its core characteristics. 
Data visualization is a tool that transforms complex data into intuitive and compelling visual representations. Using scatter plots, bar charts, histograms, heat maps, and interactive dashboards to showcase specific insights effectively. It involves selecting appropriate chart types, choosing color schemes, and labeling axes to aid the creation of impactful visualizations. 
Data visualization utilizes several techniques to visualize, analyze and find patterns in data. It involves handling data during analysis such as choosing models, correlation analysis, handling outliers, exploring relationships between variables, calculating summary statistics, visualizing data distribution. It creates a deeper understanding of data by inferring insights from massive datasets. EDA and visualization are synergistic processes that empower data scientists to uncover hidden patterns, gain insights and effectively communicate findings.
EXPLORATORY DATA ANALYSIS TECHNIQUES
1.	Descriptive Statistics: provide a summary of the central tendency, dispersion, and shape of the dataset’s distribution.  
2.	Graphical Representations: such as histograms, box plots, scatter plots, and heatmaps, provide a visual means of exploring and understanding data. To identify patterns, trends, and relationships among variables and ease the interpterion of analysis results.
3.	Inferential Statistics: used to make generalizations about a population based on a sample. Techniques like hypothesis testing, confidence intervals, and regression analysis help in making inferences about the relationships between variables and the likelihood of these relationships occurring by chance.

CONCLUSION
Exploratory Data Analysis is just a key in order to have a better understanding, representing data to build a stronger and more generalized model.