Examples of what pupils should know and be able to do
Pupils should understand that pie charts are mainly suitable for categorical data. They should draw pie charts using ICT and by hand, usually using a calculator to find angles.
They should be able to draw compound bar charts with subcategories.
They should use frequency diagrams for continuous data, and know that the divisions between bars should be labelled.
They should know that it can be appropriate to join points on a line graph in order to compare trends over time.
Probing questions
When drawing a pie chart, what information do you need to calculate the size of the angle for each category?
What is discrete data? What is continuous data? Give me some examples.
How do you go about choosing class intervals when grouping data for a bar chart or a frequency diagram?
What's important when choosing the scale for the frequency axis?
Is this graphical representation helpful in addressing the hypothesis? If not, why not and what would you change?
When considering a range of graphs representing the same data:
- Which is the easiest to interpret? Why?
- Which is most helpful in addressing the hypothesis? Why?
What if pupils find this a barrier?
Use ICT to show pupils what the finished graph should look like. Explain
how to choose the scales when drawing a graph. Plot a linear relationship
as a scatter graph to demonstrate an exact correspondence or mapping, and
then introduce a positive correlation between two sets of data.
Interacting with mathematics – handling data (DfES 0220/2002)
Phase 3
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