Problem solving with conditional probability
I can use my knowledge of conditional probability to solve problems.
Problem solving with conditional probability
I can use my knowledge of conditional probability to solve problems.
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Lesson details
Key learning points
- Probabilities may appear in unfamiliar contexts
- Probabilities may require a strong knowledge of converting between fractions, decimals and percentages
- Selecting an appropriate and efficient method for solving the problem comes from evaluating methods
- A clear, logical, structured argument is much easier to follow and understand
Keywords
Probability - The probability that an event will occur is the proportion of times the event is expected to happen in a suitably large experiment.
Exhaustive events - A set of events are exhaustive if at least one of them has to occur whenever the experiment is carried out.
Mutually exclusive - Mutually exclusive events have no outcomes in common.
Venn diagram - Venn diagrams are a representation used to model statistical/probability questions. Commonly circles are used to represent events.
Common misconception
Pupils may represent probabilities in the wrong position on the probability scale by miscounting the number of intervals required.
Before using any probability scale, it can be helpful to make a note of the sizes for each major and minor interval.
To help you plan your year 11 maths lesson on: Problem solving with conditional probability, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your year 11 maths lesson on: Problem solving with conditional probability, 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.
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Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.Mutually __________ events have no outcomes in common.
Q2.Sofia has to catch a bus and then a train to get to school. When the bus is late, Sofia is more likely to miss the train and so be late for school. Match each value to its probability.
$$x$$ -
0.2
$$y$$ -
0.25
$$z$$ -
0.9
Q3.Sofia has to catch a bus and then a train to get to school. When the bus is late, Sofia is more likely to miss the train and so be late for school. P(Sofia is late for school) = .
Q4.Here is a general probability tree. Which of these probabilities give the probability of the highlighted events?
Q5.One marble is taken at random from a bag of 7 purple and 5 green marbles. The marble is not replaced. A second marble is then taken. The tree diagram shows these two events. Find the value of $$z$$.
Q6.One marble is taken at random from a bag of purple and green marbles. The marble is not replaced. A second marble is then taken. The tree diagram shows the two events. Find P(both marbles are purple).
Assessment exit quiz
6 Questions
Q1.Starting with the least likely, put these probabilities in order of likelihood.
Q2.The probability of three outcomes to a trial are shown in the table.
The outcomes are exhaustive and mutually exclusive. Find P(C).
Q3.Jacob and Sofia each play a tennis match. Find the probability that both Jacob and Sofia win their match.
Q4.Jacob and Sofia each play a tennis match. Find the probability that at least one of them wins their match.
Q5.A box contains green and blue marbles. Some of the marbles have swirls on them. The Venn diagram shows the number of each type. P(B) = . Give your answer as a decimal.
Q6.A box contains green and blue marbles. Some of the marbles have swirls on them. The Venn diagram shows the number of each type. P(S ∪ B) = . Give your answer as a decimal.