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Which tables and diagrams suit which data, and how do you read and compare them?

Tabulation, tally, two-way tables, pictograms, pie charts, stem and leaf diagrams and Venn diagrams; choosing and justifying an appropriate representation; spotting misleading diagrams.

A focused answer to Edexcel GCSE Statistics on tabulation and diagrams, covering tally charts, two-way tables, pictograms, pie charts, stem and leaf and Venn diagrams, choosing and justifying an appropriate representation, and recognising misleading graphs.

Generated by Claude Opus 4.89 min answer

Reviewed by: AI editorial process; not yet individually human-reviewed

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  1. What this dot point is asking
  2. Tabulation and two-way tables
  3. Pictograms and pie charts
  4. Stem and leaf diagrams
  5. Venn diagrams and choosing a representation
  6. Misleading diagrams

What this dot point is asking

Edexcel codes 2a.01 to 2a.08 require you to represent and interpret data using tables and diagrams: tabulation, tally charts, two-way tables, pictograms, pie charts, stem and leaf diagrams and Venn diagrams. You must extract values, compare data sets shown in different formats, justify which representation suits which data, and recognise when a diagram misleads. Pie charts and stem and leaf diagrams are frequent calculation questions; two-way tables underpin much of the probability work later.

Tabulation and two-way tables

A tally chart records frequencies as data is collected. A two-way table cross-classifies data by two variables (for example gender against transport to school), with row and column totals. Edexcel expects you to complete missing entries using the totals and to read off frequencies. Two-way tables are also the basis for many probability questions, so fluency here pays off twice.

Pictograms and pie charts

A pictogram uses a symbol to represent a fixed number of items and always needs a key. A pie chart shows each category as a sector whose angle is proportional to its frequency.

To read a pie chart in reverse, a sector's angle as a fraction of 360∘360^\circ gives its share of the total. Pie charts compare proportions within one data set well, but comparing two pie charts of different totals needs care.

Stem and leaf diagrams

A stem and leaf diagram splits each value into a stem (the leading digits) and a leaf (the final digit), keeping every original value while ordering the data. Edexcel requires the leaves to be ordered and a key to be given (for example 1∣2=121 \mid 2 = 12). Because the data is ordered and complete, you can read off the median, quartiles, mode and range directly, which is why these diagrams are popular in exams.

Venn diagrams and choosing a representation

A Venn diagram shows overlapping sets, making it easy to count items in intersections and unions; it also feeds into probability. When asked to choose and justify a representation (codes 2a.05, 2a.08), match the diagram to the data: scatter diagrams for bivariate data, histograms for grouped continuous data, pie charts for parts of a whole, stem and leaf for small ordered sets. Consider the audience too: a simple chart may communicate better than a technical one.

Misleading diagrams

Edexcel code 2a.06 asks you to spot graphical misrepresentation. Common faults: a truncated axis (not starting at zero) that exaggerates differences, an inconsistent or non-linear scale, distorted sizing (a picture scaled in two dimensions when only the height should represent the value), and misleading 3D effects. Always check the axes and scale before drawing a conclusion.

Exam-style practice questions

Practice questions written in the style of Pearson Edexcel exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.

Edexcel 1ST0 20194 marksIn a survey of 7272 people, 3030 chose tea, 2424 chose coffee and the rest chose water. Draw a pie chart to represent this data, showing the angle for each sector.
Show worked answer →

Water =72−30−24=18= 72 - 30 - 24 = 18 people. Each person is worth 36072=5\frac{360}{72} = 5 degrees.

Tea: 30×5=15030 \times 5 = 150 degrees. Coffee: 24×5=12024 \times 5 = 120 degrees. Water: 18×5=9018 \times 5 = 90 degrees.

Check: 150+120+90=360150 + 120 + 90 = 360 degrees.

Draw three sectors of these angles and label them. Markers reward the "degrees per person" method, correct angles, the check that they total 360360, and a clearly labelled chart.

Edexcel 1ST0 20213 marksThe stem and leaf diagram shows the masses, in kg, of 1111 parcels (key 1∣21 \mid 2 means 1212 kg): stem 00 leaves 7,97, 9; stem 11 leaves 0,2,5,80, 2, 5, 8; stem 22 leaves 1,3,41, 3, 4; stem 33 leaves 2,62, 6. (a) Write down the median mass. (b) Find the range.
Show worked answer →

There are 1111 values, so the median is the 66th value when ordered. Reading in order: 7,9,10,12,15,18,21,23,24,32,367, 9, 10, 12, 15, 18, 21, 23, 24, 32, 36. The 66th value is 1818, so the median is 1818 kg.

Range == largest −- smallest =36−7=29= 36 - 7 = 29 kg.

Markers reward locating the median position with n+12=6\frac{n+1}{2} = 6, reading 1818 kg, and the correct range of 2929 kg.

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