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Graphs and data: reading charts and finding averages
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Every GCSE Geography paper has graphs, tables and calculations. Most marks come from reading values carefully and doing simple maths accurately.
Choosing and reading graphs
Line graph: shows change over time, such as temperature through the year.
Bar chart: compares separate categories, such as rainfall each month.
Pie chart: shows parts of a whole.
Climate graph: a line for temperature and bars for rainfall on the same chart.
Always read the title, the axes and the units first. Use a ruler to read values off a graph.
Bar chart: compares separate categories, such as rainfall each month.
Pie chart: shows parts of a whole.
Climate graph: a line for temperature and bars for rainfall on the same chart.
Always read the title, the axes and the units first. Use a ruler to read values off a graph.
A climate table
Look for the highest and lowest values, the pattern (when it rises and falls) and any anomalies (values that do not fit the pattern).
Describe a pattern with data: 'Temperature rises from 4 °C in January to a peak of 18 °C in July and August.'
Describe a pattern with data: 'Temperature rises from 4 °C in January to a peak of 18 °C in July and August.'
Averages and percentages
Mean: add the values and divide by how many there are.
Median: the middle value when they are in order.
Mode: the most common value.
Range: highest − lowest.
Percentage = part ÷ whole × 100. For example, 15 out of 60 people is 15 ÷ 60 × 100 = 25%.
Median: the middle value when they are in order.
Mode: the most common value.
Range: highest − lowest.
Percentage = part ÷ whole × 100. For example, 15 out of 60 people is 15 ÷ 60 × 100 = 25%.
Find the mean of 3, 8, 5, 8 and 11.
- Add them: 3 + 8 + 5 + 8 + 11 = 35.
- Divide by how many values there are: 35 ÷ 5 = 7.
Answer: 7
Read the title, axes and units first. Line graphs show change over time; bar charts compare categories. Mean = total ÷ number of values; median = middle; mode = most common; range = highest − lowest. Percentage = part ÷ whole × 100.
The interactive lesson includes the diagrams for this topic.
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