Class Intervals

TL;DR

A way to group data into ordered ranges or segments to simplify interpretation.
Facilitates counting how many observations fall into each range.
Applicable to numeric measures (e.g., heights) and grouped categorical/percentage responses (e.g., survey frequencies).

Definition

Class intervals are a way to group a set of data into manageable, organized segments. This is commonly used in statistics and data analysis to make data easier to interpret and analyze.

Explanation

Class intervals partition data into contiguous ranges (for numeric data) or grouped categories (for responses expressed as percentages or levels). By assigning each observation to the interval that contains it, you can tabulate counts or proportions per interval and thereby see the distribution of the dataset more clearly.

Examples

Heights (numeric example)

Given a set of heights, class intervals can be:

5-6 feet
6-7 feet
7-8 feet

If counts per interval are:

5-6 feet: 10 people
6-7 feet: 5 people
7-8 feet: 3 people

you can quickly see that the majority of the group is between 5-6 feet tall.

Exercise frequency (survey example)

Survey responses like “never”, “rarely”, “sometimes”, and “always” can be represented as percentage ranges:

Never: 0-10% of respondents
Rarely: 11-30% of respondents
Sometimes: 31-70% of respondents
Always: 71-100% of respondents

This shows the distribution of responses across the defined frequency categories.

Use cases

Commonly used in statistics and data analysis to make data easier to interpret and analyze.
Useful for organizing survey results into meaningful segments for distributional insight.

Statistics
Data analysis
Survey