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1.4 Representing a Categorical Variable with Graphs

Part of Exploring One-Variable Data in AP® Statistics. Read the opening section, then create a free account for the full interactive lesson, practice, and progress tracking.

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Bar Graphs

A bar graph is the most common display for categorical data.

Construction:

  1. Label the x-axis with category names
  2. Label the y-axis with frequency or relative frequency
  3. Draw bars of equal width — the height represents each category's count or proportion
  4. Bars do NOT touch (unlike histograms)

Comparative bar graph — useful for comparing distributions between groups.

When interpreting: note which categories are most/least frequent, and comment on any large differences between groups.

In this unit

10 lessons

  1. 1.1Introducing Statistics: What Can We Learn from Data?Preview lesson
  2. 1.2The Language of Variation: VariablesPreview lesson
  3. 1.3Representing a Categorical Variable with TablesPreview lesson
  4. 1.4Representing a Categorical Variable with GraphsThis lesson
  5. 1.5Representing a Quantitative Variable with GraphsPreview lesson
  6. 1.6Describing the Distribution of a Quantitative VariablePreview lesson
  7. 1.7Summary Statistics for a Quantitative VariablePreview lesson
  8. 1.8Graphical Representations of Summary StatisticsPreview lesson
  9. 1.9Comparing Distributions of a Quantitative VariablePreview lesson
  10. 1.10The Normal DistributionPreview lesson

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