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A diagram for grouped continuous data in which bars cover the class intervals and bar areas represent frequencies.

A graph of grouped numerical data with touching bars spanning the class intervals. Bar areas are proportional to frequencies.

A histogram puts the class boundaries on a numerical horizontal scale. Draw a bar spanning each interval, with adjacent bars touching. All four intervals here have width 10 minutes, so their heights can be their frequencies: 4, 8, 6 and 2.

A diagram for grouped continuous data in which each rectangle spans a class interval and its area is proportional to the frequency.

For equal-width histograms, the vertical axis may be labelled ‘Frequency’. This convention does not extend to unequal-width histograms.

For a histogram, show the class widths and frequency-density calculations. Check your answer using frequency = frequency density × class width.

For unequal-width histogram classes, frequency is represented by bar area, not bar height.

A graph of grouped continuous data in which rectangle areas represent frequencies.

Histogram

Definition

How each exam board covers it

Edexcel GCSE Statistics · 1ST0

Exam tips

Revise Statistics with GradeGen

Definition

How each exam board covers it

Edexcel GCSE Statistics · 1ST0

Exam tips

Related key terms

Revise Statistics with GradeGen