Learn on PengiReveal Math, Course 1Module 10: Statistical Measures and Displays

10-4 Interquartile Range and Box Plots

In this Grade 6 lesson from Reveal Math, Course 1, Module 10, students learn how to calculate measures of variation, including range, quartiles, and interquartile range (IQR), to describe the spread of a data set. Students practice finding Q1, Q2, and Q3 by dividing ordered data into four equal parts, then computing the IQR using the formula Q3 minus Q1. The lesson also introduces box plots as a visual tool for displaying the five-number summary of a data set on a number line.

Section 1

Quartiles and the Importance of Ordering Data

Property

While the "Range" (Maximum - Minimum) tells us the total spread of a data set, it doesn't tell us how the data behaves in the middle. To analyze the spread better, we divide the data into four equal parts called Quartiles.
Before finding any quartiles, the data set MUST be ordered from least to greatest.

  • Q2 (Median): The middle of the entire data set.
  • Q1 (First Quartile): The median of the lower half of the data.
  • Q3 (Third Quartile): The median of the upper half of the data.

Examples

Book overview

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Module 10: Statistical Measures and Displays

  1. Lesson 1

    10-1 Statistical Questions

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  2. Lesson 2

    10-2 Dot Plots and Histograms

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  3. Lesson 3

    10-3 Measures of Center

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  4. Lesson 4Current

    10-4 Interquartile Range and Box Plots

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  5. Lesson 5

    10-5 Mean Absolute Deviation

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  6. Lesson 6

    10-6 Outliers

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  7. Lesson 7

    10-7 Interpret Graphical Displays

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Lesson overview

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Section 1

Quartiles and the Importance of Ordering Data

Property

While the "Range" (Maximum - Minimum) tells us the total spread of a data set, it doesn't tell us how the data behaves in the middle. To analyze the spread better, we divide the data into four equal parts called Quartiles.
Before finding any quartiles, the data set MUST be ordered from least to greatest.

  • Q2 (Median): The middle of the entire data set.
  • Q1 (First Quartile): The median of the lower half of the data.
  • Q3 (Third Quartile): The median of the upper half of the data.

Examples

Book overview

Jump across lessons in the current chapter without opening the full course modal.

Continue this chapter

Module 10: Statistical Measures and Displays

  1. Lesson 1

    10-1 Statistical Questions

    LearnPractice
  2. Lesson 2

    10-2 Dot Plots and Histograms

    LearnPractice
  3. Lesson 3

    10-3 Measures of Center

    LearnPractice
  4. Lesson 4Current

    10-4 Interquartile Range and Box Plots

    LearnPractice
  5. Lesson 5

    10-5 Mean Absolute Deviation

    LearnPractice
  6. Lesson 6

    10-6 Outliers

    LearnPractice
  7. Lesson 7

    10-7 Interpret Graphical Displays

    LearnPractice