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Bar Charts

FoundationChallengeAQAEdexcelOCR

This free Foundation GCSE Maths worksheet on bar charts helps you revise drawing and interpreting bar charts. Questions build from straightforward to exam standard, with full worked answers in the mark scheme — ideal for revision or homework. Suitable for AQA, Edexcel and OCR. Leave equal gaps between bars and use a consistent scale.

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These worksheets and mark schemes are original, written for Virtus Academy and checked against the current AQA, Edexcel and OCR specifications. Every worksheet comes with a full mark scheme.

Foundation

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Challenge / Extension

Stretch yourself beyond the basics.

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Topic overview

A bar chart displays data using bars whose heights show the frequency of each category. It is used for discrete or categorical data.

The bars must be of equal width and separated by gaps, which distinguishes a bar chart from a histogram. The gaps show that the categories are separate rather than continuous.

Axes must be labelled and the scale must be even. Marks are commonly lost for an unlabelled axis or an inconsistent scale, so those two things are worth checking before anything else.

Revision notes

Drawing a bar chart

Draw bars of equal width with gaps between them, with heights matching the frequencies.

Label both axes and give the chart a title. Use a sensible even scale on the frequency axis.

Reading values

Read the height of a bar against the frequency axis, using a ruler to stay level.

Check the scale carefully: if each square represents \(2\), a bar reaching the fourth line shows a frequency of \(8\).

Comparative bar charts

A dual bar chart shows two sets of data side by side for each category, with a key explaining the colours.

A composite bar chart stacks them instead, so the total height gives the combined frequency.

Key points

  • Bars have equal width with gaps between them.
  • Height shows the frequency.
  • Used for discrete or categorical data.
  • Both axes must be labelled.
  • The scale must be even.
  • Dual bar charts need a key.

Worked examples

Example 1

A bar reaches the height \(14\) on the frequency axis. What does this show?

Working

\[\text{Height represents frequency}\]read the axis
\[\text{That category occurred 14 times}\]interpret in context

Example 2

Each square represents \(5\) and a bar is \(3\) squares tall. Find the frequency.

Working

\[3 \times 5\]multiply squares by the scale
\[= 15\]state the frequency

Example 3

Why do bar charts have gaps between the bars?

Working

\[\text{The categories are separate}\]the data is not continuous
\[\text{Gaps show they are distinct}\]this distinguishes it from a histogram

Common mistakes

  • Drawing bars of unequal width.

    All bars must be the same width so the heights can be compared fairly.

  • Omitting gaps between bars.

    That would make it look like a histogram, which is for continuous data.

  • Using an uneven scale.

    The frequency axis must increase in equal steps.

  • Forgetting to label the axes.

    Both axes need labels, and a key is needed for dual charts.

Exam tips

  • Check the scale before reading any bar.
  • Use a ruler to read heights accurately.
  • Label both axes and add a key if needed.
  • Keep bar widths equal and leave gaps between them.

Key terms

Bar chart
A chart using bars to show frequencies.
Categorical data
Data sorted into named groups.
Key
A guide explaining what each colour represents.
Scale
How much each division on an axis represents.

Related topics

Written and reviewed against the current AQA, Edexcel and OCR specifications. Spotted an error? Let us know.