Problem Page

Pupils interpret the graph provided to give advice on the statistical “acceptability” of age gaps in relationships.

Practical details

Suitability
National Curriculum levels 6 to 8
Time
45 minutes to 1 hour
Resources
Paper

Key Processes involved

Representing
Identify key features of a graph
Analysing.
Use equations and / or inequalities to describe these features
Interpreting and evaluating
Interpret the graph to give advice
Communicating and reflecting
Reflect on how well the graph matches real life

Teacher guidance

Check that pupils understand the context before they begin, for example, by saying:

• There is a graph which shows what some people think is an acceptable age difference between people in a relationship.
• You need to use this graph to provide the advice.

The task requires an understanding of linear graphs.

During the work, the following probing questions may be helpful:

• Are there any important differences between Jenny’s information and Tim’s?
• Is there a way you can work out an acceptable age gap for any age?
• Are there are any other issues you need to consider?
• Would people use this rule in the real world? Why - or why not?

There are three key aspects to this task:

1. Interpret the graph: what the lines and the green area represent.
2. Define the equations of the lines for the ‘acceptable’ age limits for any given age.
3. Apply this to Jenny and Tim’s questions, giving them informed and relevant advice.

Pupils should also reflect on the rule of the ‘half the older one and add seven’ in the real world: is it an appropriate rule to judge the success (or otherwise) of a relationship?