How to Build and Read a Frequency Distribution

Frequency distributions show how often each value of a variable occurs — one of the fastest ways to get a feel for your data.

How to build a frequency table

For a categorical variable, you count how many times each category occurs. For a continuous variable, the data is first split into intervals (bins), and then the number of observations falling into each bin is counted.

Absolute vs. relative frequency

Absolute frequency is the raw count of how many times a value occurs. Relative frequency is that count divided by the total number of observations (usually expressed as a percentage) — relative frequency is more useful when comparing datasets of different sizes.

Example: In a survey of 200 respondents, if 50 chose “very satisfied,” the absolute frequency is 50 and the relative frequency is 25%.

Visualizing with a histogram

• Too few bins and the shape of the distribution gets lost.
• Too many bins and noise overwhelms the real pattern.
• As a rule of thumb, a number of bins close to the square root of the sample size is a reasonable starting point.

A frequency distribution is the first thing worth checking before any analysis: skewness, multiple modes, or unexpected gaps in the data all show up at this stage.