Hassan Ijaz

Ai, Web & Design
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Descriptive StatisticsTopic 9 of 58

Data visualization and EDA

Dashboard builder where users drag different chart types and see how same data tells different stories

Concept Overview

Data visualization and exploratory data analysis (EDA) are essential first steps in any data analysis project. Good visualizations reveal patterns, outliers, and relationships that might be hidden in raw numbers.

Core Visualization Types

Histogram

Shows distribution shape, spread, and outliers

Best for: Single continuous variable

Scatter Plot

Reveals relationships between two variables

Best for: Bivariate continuous data

Box Plot

Shows quartiles, median, and outliers

Best for: Comparing distributions

Bar Chart

Compares categorical values

Best for: Categorical data counts

Line Plot

Shows trends over time or sequence

Best for: Time series data

Heatmap

Displays correlation or 2D density

Best for: Matrix data, correlations

EDA Process

  1. Check Data Quality - Missing values, duplicates, data types
  2. Univariate Analysis - Examine each variable individually
  3. Bivariate Analysis - Explore relationships between pairs
  4. Multivariate Analysis - Look at multiple variables together

Visual Encoding Principles

Effectiveness of visual channels (in order):

  1. Position along a scale
  2. Length/Distance
  3. Area
  4. Volume
  5. Color/Density

Use position for most important comparisons!

Common Pitfalls

  • Starting y-axis above zero (misleading bar charts)
  • Using 3D effects (distorts perception)
  • Too many colors or categories
  • Pie charts for many categories
  • Ignoring aspect ratios

The Power of Multiple Views

The same data can tell different stories depending on visualization choice. Always try multiple chart types to gain different perspectives. What looks random in a table might show clear patterns in a scatter plot!

The dashboard builder below lets you drag different chart types onto the same dataset. See how different visualizations reveal different aspects of the data's story.

Interactive Visualization

Loading interactive visualization...

Dashboard builder where users drag different chart types and see how same data tells different stories