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Class 8 Maths — Grouped data, histograms and pie charts

Group data into class intervals, read a histogram, and work out the angles in a pie chart.

Name: ________________________

Before you start

This pie chart shows what a class of 40 children picked for their club. Find out what each slice is and how wide its angle is — nothing here is right or wrong.

1234
  1. 1. Reading — 90°, so 10 children
  2. 2. Sport — 90°, so 10 children
  3. 3. Music — 108°, so 12 children
  4. 4. Art — 72°, so 8 children

The four angles add up to 360°, one whole turn. Music is the biggest slice because 12 out of 40 is the biggest share — and 12/40 of 360° really is 108°.

  1. 1.A class interval runs from 20 to 30. What is its class size?

  2. 2.This histogram shows the marks of a class. Tap the interval that holds the most students.

    Write the number of the part.

    1234

  3. 3.A pie chart is split between 4 subjects with an equal share each. What angle does each sector take, in degrees? Give just the number.

  4. 4.Match each share of the whole to the angle of its sector in a pie chart, in degrees.

    • Half
    • A quarter
    • A third
    • A fifth
    • A tenth
    • 180
    • 36
    • 120
    • 90
    • 72

  5. 5.Data is grouped as 10-20, 20-30 and 30-40. Which interval does a value of exactly 20 belong to?

    • a) 10-20
    • b) Both of them
    • c) 20-30
    • d) Neither of them

  6. 6.What is the main difference between a bar graph and a histogram?

    • a) A histogram has to be drawn in colour
    • b) A bar graph cannot show how many there are of anything
    • c) A histogram has no gaps between its bars, because its classes run on from each other
    • d) A histogram always has more bars than a bar graph

  7. 7.In a pie chart of 60 students, 15 of them chose reading. What angle does that sector take, in degrees? Give just the number.

  8. 8.A pie chart shows 200 people. One sector measures 72 degrees. How many people does that sector stand for?

Answer key — Class 8 Maths — Grouped data, histograms and pie charts

  1. 1. 10
  2. 2. 2 — 10 to 20 marks — 9 students
  3. 3. 90
  4. 4. Half → 180; A quarter → 90; A third → 120; A fifth → 72; A tenth → 36
  5. 5. c) 20-30
  6. 6. c) A histogram has no gaps between its bars, because its classes run on from each other
  7. 7. 90
  8. 8. 40