Class interval
This page provides the definition for a mathematics term.
About this resource
A glossary of terms used in mathematics.
Class interval
One of the non-overlapping intervals into which the range of values of measurement data, and occasionally whole-number data, is divided. Each value in the distribution must be able to be classified into exactly one of these intervals.
Example 1 (measurement data)
The number of hours of sunshine per week in Grey Lynn, Auckland, from Monday, January 2, 2006, to Sunday, December 31, 2006, is recorded in the frequency table below. The class intervals used to group the values of weekly hours of sunshine are listed in the first column of the table.
| Hours of sunshine | Number of weeks |
|---|---|
| 5 to less than 10 10 to less than 15 15 to less than 20 20 to less than 25 25 to less than 30 30 to less than 35 35 to less than 40 40 to less than 45 45 to less than 50 |
2 2 5 9 12 10 5 6 1 |
| Total | 52 |
Example 2 (whole-number data)
Students enrolled in an introductory statistics course at the University of Auckland were asked to complete an online questionnaire. One of the questions asked them to enter the number of countries they had visited other than New Zealand. The class intervals used to group the values are listed in the first column of the table.
| Number of countries visited | Frequency |
|---|---|
| 0–4 5–9 10–14 15- 19 20- 24 25–29 30–34 |
446 172 69 19 14 4 3 |
| Total | 727 |
Alternatives: bin, class
Curriculum achievement objectives references
Statistical investigation: Levels 4, 5, 6, 7, 8
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