Sheet № 248 · Foundation + Higher · AQA · Edexcel · OCR
Interpreting Data from Tables and Charts –
Interpreting data from tables and charts is one of the most widely tested skills on GCSE Maths papers across AQA, Edexcel and OCR at both Foundation and Higher tier. Questions ask you to read values, calculate totals or percentages, compare data, draw conclusions and identify limitations. Strong data interpretation skills are also needed
§Key definitions
Interpreting data
means extracting useful information from tables, bar charts, pie charts, line graphs, pictograms or other statistical diagrams. It includes:
(a)
Total = 5 + 12 + 18 + 10 + 5 = 50 students.
(b)
Fraction = 18/50 = 9/25.
Answer:
(a) 50 students. (b) 9/25.
(c)
Increase = 110 − 85 = 25. Percentage increase = (25 ÷ 85) × 100 = 29.4% (1 d.p.).
§Formulas to memorise
Percentage = (part ÷ whole) × 100
Fraction of total = frequency ÷ total frequency
Percentage change = (change ÷ original) × 100
Read the title, labels and key — understand what the data represents, what units are used and what each axis or column shows.
Read values carefully — use a ruler on printed papers to align with axes accurately.
Calculate as required — find totals by adding, differences by subtracting, and percentages using the formula above.
Draw conclusions — link your calculations to the context. Use phrases like "this suggests that..." or "the data shows that..."
State limitations — consider sample size, whether the data is representative, whether other factors could explain the results, and whether the source is reliable.
Worked example
A bar chart shows the number of books read by students in a month: 0 books — 5 students, 1 book — 12 students, 2 books — 18 students, 3 books — 10 students, 4+ books — 5 students. (a) How many students were surveyed? (b) What fraction read
Working:
⚠ Common mistakes
- ✗Misreading scales. Check whether the scale goes up in 1s, 5s, 10s or another increment. A common error is reading a bar that sits between gridlines.
- ✗Confusing frequency with percentage. If the chart shows frequencies, you must calculate the percentage separately — do not assume the bar heights are percentages.
- ✗Drawing conclusions beyond the data. Only make claims that the data supports. If asked for a limitation, mention sample size, time period or possible bias.
- ✗Forgetting units. Always include units (£, km, %) in your answer.
✦ Exam tips
- →On non-calculator papers, use fractions where possible — they are easier to work with than decimals.
- →When a question says "give a reason for your answer", refer to a specific number from the data.
- →For "evaluate this claim" questions, calculate the actual values and compare them to the claim.
- →For chart-drawing skills, see bar charts, pie charts and pictograms. For misleading data, see misleading graphs and data.