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Learn4MA1Papers 1F, 2F · Foundation tierStatistics and probabilityCharts, tables and scatter diagrams
Statistics and probability · Subtopic 3 of 7

Charts, Tables and Scatter Diagrams

A pie chart shares 360∘360^\circ in proportion to the frequencies. A two-way table splits a group by two features at once. A scatter diagram shows whether two quantities are related, and a line of best fit lets you estimate one from the other within the range of the data.

Cambridge 4024 Paper 1Cambridge 4024 Paper 2Edexcel 4MA1 Papers 1H, 2HEdexcel 4MA1 Papers 1F, 2FAQA 8300 Papers 1–3≈ 30 minRevision 5 · updated 2026-10-27
Section 1 of 14

Learning objectives

  • Calculate pie-chart angles and read frequencies from them.
  • Complete and use two-way tables.
  • Describe correlation on a scatter diagram.
  • Use a line of best fit, and know when it is unreliable.
Pause and think

Towns with more ice-cream sales also have more sunburn cases. Does ice cream cause sunburn?

Section 2 of 14

Core idea

Start hereA picture of a relationship

Do taller people have bigger hands? Plot each person as a dot and the pattern jumps out. Pie charts, meanwhile, show at a glance what share each group takes.

The big idea

Pie chart angle = frequency × 360total\frac{360}{\text{total}}. Scatter diagrams show correlation; a line of best fit estimates within the data range.

1. Scatter diagrams

Scatter diagram: hours revised vs test score, with a line of best fit
246810204060801000hours revisedscoreline of best fit
Positive correlation: more revision tends to go with higher scores. Use the line to estimate, e.g. 4.5 hours → about 54.
  • Positive, negative or no correlation.
  • Line of best fit through the middle (and the mean point).
  • Estimate only within the data.
Common misconceptionCorrelation is not causation Two things rising together may both be caused by a third.

2. Pie charts

Pie chart: 60 students' favourite sport
football 30cricket 20tennis 106° per student
360∘÷60=6∘360^\circ\div60=6^\circ per student: football 180∘180^\circ, cricket 120∘120^\circ, tennis 60∘60^\circ.
Worked example72 people travel

30 walk, 24 bus, 18 car.

Goal
Angles.
Strategy
Degrees per person.
  1. 360÷72=5∘360\div72=5^\circ
    Per person.
  2. 150∘, 120∘, 90∘150^\circ,\ 120^\circ,\ 90^\circ
    Multiply.
Answer150∘150^\circ, 120∘120^\circ, 90∘90^\circ.
✓ CheckSum 360∘360^\circ ✓.
Pause and think

A 45∘45^\circ sector represents 30 people. Total?

Summary

  • Angle = f × 360 ÷ total.
  • Correlation ≠ causation.
Key words
Correlation
Relationship between two variables.
HistoryA nurse with a pie chart. Florence Nightingale used a circular "rose diagram" in 1858 to show that far more soldiers in the Crimean War died from disease in hospitals than from wounds. Her chart helped persuade the British government to improve hospital sanitation.
Fun factSilly correlations. Websites collect real but meaningless correlations, such as cheese eaten per person in the US tracking deaths from tangled bedsheets. With enough data sets, some will move together by pure chance.
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