Fractile v. Equal Lesson for Grades 7-10

Students work with data that represent the ages of 24 people to learn the difference between categorizing data in fractile intervals and equal intervals. Students discuss dividing bonus points among class members to understand what per capita means. Then students search for state-level data on personal income per person and visualize them in FRED. The goals are for students to customize a map, observe patterns in mapped data, and note differences across geographical areas.

Economic and Statistical Concepts Covered in this Lesson

  • Equal intervals: Data ranges of equally sized intervals.
  • Fractile intervals: Data ranges with the same number of data points per interval.
  • Income: Payment people earn for the work they do.
  • Per capita personal income: The total income per person in a region determined by dividing the total income by the total population.


Students will be able to:

  • explain the differences between equal intervals and fractile intervals,
  • define personal income and per capita personal income; and
  • compare tables and maps of the same data displayed with equal intervals and with fractile intervals.

Compelling Question

How do fractile and equal intervals create different data categories?


If you have difficulty accessing this content due to a disability, please contact us at 314-444-8624 or

Find More Economics and Personal Finance Resources

Education Level: 9-12
Subjects: Economics Geography
Concepts: Income
Resource Types: Charts/Graphs Data Lesson
Languages: English
Back to Top