Block 1

Deepak Tanwar

Introduction

• Name
• Research group
• Topic of research
• Datasets for your research
• Why are you attending this course?

Quiz 1

Questions 1 to 4

Why choosing the right chart matters?

• Effective visualizations communicate data clearly and efficiently.
• The wrong chart can mislead or confuse your audience.
• Good visualizations highlight patterns, trends, and outliers.

Types of data

• Categorical: Names or labels (e.g., Region, Product Type)
• Numeric: Quantitative values (e.g., Sales, Temperature)
• Time: Dates or time intervals (e.g., Monthly Revenue)
• Geographic: Locations (e.g., Country, Coordinates)

What to use for each type?

Categorical Data

• Use bar charts to compare categories

Categorical Data

• Use pie charts to show proportions

Numeric Data

• Use histograms to show distributions

Numeric Data

• Use boxplots to show spread and outliers

Relational Data

• Use scatter plots to show relationships between two numeric variables

Time Series Data

• Use line charts to show trends over time

Geographic Data

• Use choropleth maps to show values by region

Conclusion: Choosing the Right Visualization

• There is no single “correct” chart for a given dataset. For example, numeric data can be shown as:
  • Histogram (distribution)
  • Boxplot (spread and outliers)
  • Density plot (smooth distribution)

Conclusion: Choosing the Right Visualization

• The best choice depends on:
  • Your goal: Compare, show distribution, highlight relationships?
  • Audience: Technical vs. non-technical
  • Clarity: Which chart communicates the message most clearly?

        A       B       C
1   apple  banana    kiwi
2  banana    date     fig
3  cherry    kiwi   lemon
4    date  orange   mango
5    kiwi    pear   berry
6  orange     fig    pear
7    pear   grape coconut
8    plum   melon   guava
9   mango   peach  papaya
10 papaya apricot    plum

        A       B       C
1   apple  banana    kiwi
2  banana    date     fig
3  cherry    kiwi   lemon
4    date  orange   mango
5    kiwi    pear   berry
6  orange     fig    pear
7    pear   grape coconut
8    plum   melon   guava
9   mango   peach  papaya
10 papaya apricot    plum

        A       B       C
1   apple  banana    kiwi
2  banana    date     fig
3  cherry    kiwi   lemon
4    date  orange   mango
5    kiwi    pear   berry
6  orange     fig    pear
7    pear   grape coconut
8    plum   melon   guava
9   mango   peach  papaya
10 papaya apricot    plum

Tip: Start with the simplest chart that answers the question.

From data to visualization

Only resource you need: data-to-viz.com

Exercise: Read and discuss content

Group 1: data-to-viz.com/caveat/bin_size.html

Group 2: data-to-viz.com/caveat/consistency.html

Group 3: data-to-viz.com/caveat/simpson.html

Group 4: data-to-viz.com/caveat/boxplot.html

1. What is the main problem or risk highlighted by this caveat?
2. Why does this issue occur?
3. What are the potential consequences of ignoring this caveat?
4. How can we detect or avoid this problem in practice?

Quiz 2

Questions 5 to 12