Step 5 Objective

Understand and use the probability scale from 0 to 1.

Examples of what pupils should know and be able to do

Pupils should begin by using a line divided using this language

probability line with impossible, even and certain clearly marked

Then move them onto a 0 to 1 scale.

They should be able to estimate where a probability lies on the scale for a described event.

Probing questions

Where on the line would you put the event ... ?

Is ... more likely than ... ?

What if pupils find this a barrier?

Ask pupils to place statements on the line. Focus on two or three events which are likely but where one is more likely than the others. Pupils need to find relative positions in the right-hand side of the scale.