A bar graph compares separate categories; a pictogram encodes their counts with a key. A line graph connects successive times to reveal change. Read the axes and key before comparing heights or slopes. Example The travel survey counts bus 12, walk 8, car 4. These displays encode the same counts. Twice as many pupils walk as travel by car: 8 4=2. Bus exceeds walking by 4 pupils, shown by one extra pictogram circle. A separate line graph records a shop’s sales at equally spaced months. Sales decreased by 5 from February to March, then increased by 15 from March to April. April has the highest recorded sales. Joining the points helps show change; it does not establish the sales on every day between the monthly observations. Equal horizontal gaps should represent equal time intervals. For a pictogram with one circle representing four pupils, a half circle would represent two; enlarging a symbol’s area without a consistent key can mislead.

A bar graph compares separate categories; a pictogram encodes their counts with a key. A line graph connects successive times to reveal change. Read the axes and key before comparing heights or slopes.

The travel survey counts bus \(12\), walk \(8\), car \(4\). These displays encode the same counts.

Twice as many pupils walk as travel by car: \(8\div4=2\). Bus exceeds walking by \(4\) pupils, shown by one extra pictogram circle.

A separate line graph records a shop’s sales at equally spaced months.

Sales decreased by \(5\) from February to March, then increased by \(15\) from March to April. April has the highest recorded sales. Joining the points helps show change; it does not establish the sales on every day between the monthly observations.

Equal horizontal gaps should represent equal time intervals. For a pictogram with one circle representing four pupils, a half circle would represent two; enlarging a symbol’s area without a consistent key can mislead.

Reading bar graphs, pictograms and line graphs

Reading bar graphs, pictograms and line graphs