6 Data Visualization Free Online FlashCards

What should guide your choice of chart?

Choose a chart to answer the question you want readers to understand, not simply because the chart type looks familiar.

When is a bar chart useful?

Use a bar chart to compare values across categories, such as books borrowed from different libraries.

When is a line chart useful?

Use a line chart to show how a value changes over time, such as monthly temperatures across a year.

What does a histogram show?

A histogram shows frequencies across value ranges, making it useful for exploring how numerical values are distributed.

What is a scatter plot suited to showing?

Use a scatter plot to explore whether two numerical variables move together. Each point represents one observation.

How can a chart show a total divided into parts?

A stacked bar chart shows how a total is divided into parts. A pie chart can also work when there are only a few clearly distinct parts.

Why should you check the denominator behind a percentage?

A percentage needs a denominator: 20% of 50 people and 20% of 5,000 people represent different numbers of people.

Where should the axis of a magnitude-comparison bar chart generally start?

Bar charts comparing magnitudes should generally start at zero because bar length encodes value.

What can a mean conceal about data?

A mean can hide variation or extreme values. A histogram or box plot can reveal more about the distribution.

Does a relationship in a scatter plot prove causation?

A scatter plot can show that two variables vary together, but this alone does not prove that one causes the other.

How should a chart communicate uncertainty in sample-based estimates?

Sample-based estimates are not exact. When relevant, show uncertainty intervals or explain limitations, and avoid treating small differences as certain.

What information helps readers understand a chart's message and context?

Use a concise headline for the main pattern and a caption for the measure, population or geography, and time period. Label axes with units and identify the data source.