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Cotmanhay Junior School

Safe, Happy Learning

Week 11 Statistics

National curriculum content


  • Interpret and construct pie charts and line graphs and use these to solve problems
  • Calculate and interpret the mean as an average


Lesson objectives


  1. Line graphs
  2. Dual bar charts
  3. Read and interpret pie charts
  4. Pie charts with ercentages
  5. Draw pie charts
  6. The mean


What we want children to know


  • Pupils connect their work on angles, fractions and percentages to the interpretation of pie charts.
  • Encounter and draw graphs relating two variables, arising from their own enquiry and in other subjects.
  • Connect conversion from kilometres to miles in measurement to its graphical representation.
  • Know when it is appropriate to find the mean of a data set.


What skills we want children to develop


Use knowledge to solve reasoning and problem solving questions such as:


True or false?

(Looking at a pie chart) “More than twice the number of people say their favourite type of T.V. programme is soaps than any other”


Is this true or false?

Convince me.

Make up your own ‘true/false’ statement about the pie chart.


Missing information

The mean score in six test papers in a spelling test of 20 questions is 15.

Five of the scores were 13  12  17  18  16

What was the missing score?


Make up an example

Make up a set of five numbers with a mean of 2.7


Possible answers

a, b and c are integers between 0 and 5.


a + b = 6

b + c = 4


Find the values of a, b and c.

How many different possibilities can you find?


Vocabulary/Mathematical Talk


  • Where might you see a line graph used in real life?
  • How can you make sure that you read the information accurately?
  • What will the x/y-axis represent? What intervals will you use?
  • How will you make it clear which line represents which set of data?
  • Why is it useful to have both sets of data on one graph?
  • How is the information organised? Is it clear?
  • What else does this graph tell you/not tell you?
  • How can you calculate ________?
  • Why would this information be placed on a line graph and not a different type of graph?
  • Why is the centre important?
  • What is the relationship between the diameter and the radius? If you know one of these, how can you calculate the other?
  • Can you use the vocabulary of a circle to describe and compare objects in the classroom?
  • What does the whole pie chart represent? What does each colour represent?
  • Do you recognise any of the fractions? How can you use this to help you?
  • How did you calculate the percentage? What fraction knowledge did you use?
  • If you know 5 % of a number, how can you work out the whole number? If you know what 5 % is, what else do you know?
  • How many degrees are there around a point? How will this help us construct a pie chart?
  •  If the total frequency is ____ , how will we work out the number of degrees representing each sector?
  • If 180˚ represents 15 pupils. How many people took part in the survey? Explain why.
  • If we know the total, how can we calculate the mean?
  •  Do you think calculating the mean age of the family is a good indicator of their actual age? Why?
  • When will the mean be useful in real life?