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Different Types of Class Intervals

Part of Grouped Data — GCSE Mathematics

This deep dive covers Different Types of Class Intervals within Grouped Data for GCSE Mathematics. Revise Grouped Data in Statistics for GCSE Mathematics with 14 exam-style questions and 20 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 6 of 7 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.

Topic position

Section 6 of 7

Practice

14 questions

Recall

20 flashcards

Different Types of Class Intervals

Continuous Data (most common)

  • Format: 10 ≤ x < 20, 20 ≤ x < 30
  • Midpoint: (10 + 20) ÷ 2 = 15
  • Class width: 20 - 10 = 10

Discrete Data

  • Format: 1-5, 6-10, 11-15
  • Midpoint: (1 + 5) ÷ 2 = 3
  • Class boundaries: 0.5-5.5, 5.5-10.5, 10.5-15.5

Unequal Class Widths

Sometimes classes have different widths. Each interval is treated separately, but calculations follow the same principles.

Keep building this topic

Read this section alongside the surrounding pages in Grouped Data. That gives you the full topic sequence instead of a single isolated revision point.

Exam Tips for Grouped DataCumulative Frequency for MedianMaking Sense of Large DatasetsKey Facts About Grouped Data

Practice Questions for Grouped Data

A frequency table uses the class intervals shown below. | Speed, s (mph) | Frequency | |---|---| | 0 < s ≤ 20 | 4 | | 20 < s ≤ 40 | 11 | | 40 < s ≤ 60 | 9 | | 60 < s ≤ 80 | 2 | A car travels at exactly 40 mph. Which class interval does this value belong to?

  • A. 20 < s ≤ 40
  • B. 0 < s ≤ 20
  • C. 40 < s ≤ 60
  • D. It could belong to either 20 < s ≤ 40 or 40 < s ≤ 60
1 markfoundation

A teacher groups 30 students' test scores into four class intervals and calculates the estimated mean and estimated median. Explain why both the estimated mean and the estimated median from grouped data are only approximations of the true values. In your answer, refer to the assumptions made.

3 marksstandard

Quick Recall Flashcards

What is grouped data?
Grouped data is when individual data values are organized into classes or intervals. For example, heights might be grouped as 150-160cm, 160-170cm, etc.
What is class width?
Class width is the size of each class interval. For '10 ≤ x < 20', the class width is 20 - 10 = 10. Equal class widths make data easier to analyze.

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Cumulative Frequency for Median