Conditional probability in a two-way table
I can calculate a conditional probability from a two-way table.
Conditional probability in a two-way table
I can calculate a conditional probability from a two-way table.
These resources will be removed by end of Summer Term 2025.
Lesson details
Key learning points
- A two-way table can be used to calculate conditional probabilities
- A two-way table can be used to calculate conditional probabilities involving sets of events
- Two-way tables allow us to identify which events are mutually exclusive
- Two-way tables can be used to identify which events are independent
Keywords
Conditional probability - Conditional probability is the probability of an outcome occurring given that another event has occurred.
Mutually exclusive - Mutually exclusive events have no outcomes in common.
Independent events - Event A is independent of event B if the probability of event A occurring is not affected by whether or not event B occurs.
Common misconception
Pupils may conflate the meaning of mutually exclusive with the meaning of independent.
Emphasise the word 'exclusive' in 'mutually exclusive' to suggest that one event excludes the other. Also, emphasise that the opposite of independent is dependent.
To help you plan your year 11 maths lesson on: Conditional probability in a two-way table, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your year 11 maths lesson on: Conditional probability in a two-way table, download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
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The assessment exit quiz will test your pupils' understanding of the key learning points.
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Explore more key stage 4 maths lessons from the Conditional probability unit, dive into the full secondary maths curriculum, or learn more about lesson planning.
Licence
Starter quiz
6 Questions



Exit quiz
6 Questions

P(blue) -
$$28\over 60$$
P(green) -
$$32\over 60$$
P(blue and has no swirl) -
$$11\over 60$$
P(blue given it has no swirl) -
$$11\over 27$$
P(green and has a swirl) -
$$16\over 60$$
P(green given it has swirl) -
$$16\over 33$$
