In this unit of work we are going to look at teaching combined event probability.
The unit focuses on helping learners to understand the different ways of diagrammatically representing combined probability situations and uses contextual examples, questions and games, which can often be challenging and time consuming for the teacher to prepare.
Some learners find the jump to combined event probability challenging, and struggle to appreciate that calculating probabilities for combined events is similar to single events, in that it amounts to nothing more than counting up the number of equally likely outcomes that fit a particular situation.
Learners following an extended curriculum, may not recognise that conditional probability favours the use of some approaches over others.
The unit starts by using possibility space diagrams to establish basic principles, and then explores how probabilities can be calculated using fraction arithmetic to arrive at the same answer with less effort. Having multiplied probabilities together to calculate combined events, tree diagrams are introduced.
Learners following the extended curriculum will need to be able to solve problems involving conditional probability, and it is common for students to miss the condition. A separate lesson focusing on this skill, and the importance of understanding the language surrounding conditional probability, is included to address this issue.
This unit of work is just one of several approaches that you could take when teaching this topic, and you should aim to adapt the resources to match ability level of your learners, as well as your school context.