Myths about teaching can hold you back
- Year 9
Calculating theoretical probabilities from probability tree diagrams (one event)
I can find theoretical probabilities from a probability tree diagram showing the possible outcomes for one event.
- Year 9
Calculating theoretical probabilities from probability tree diagrams (one event)
I can find theoretical probabilities from a probability tree diagram showing the possible outcomes for one event.
Lesson details
Key learning points
- The probability of an outcome can be found by considering a probability tree diagram showing all possible outcomes.
- The probability of a set of outcomes can be found by considering a probability tree showing all possible outcomes.
- A probability tree can help us find a probability, even when the outcomes are not equally likely.
Keywords
Probability tree - Each branch of a probability tree shows a possible outcome from an event or from a stage of a trial, along with the probability of that outcome happening.
Common misconception
A probability tree can only have two branches.
A probability tree can have any number of branches on a layer, but the more branches you want to include, the trickier and less practical the probability tree is to draw and use.
To help you plan your year 9 maths lesson on: Calculating theoretical probabilities from probability tree diagrams (one event), download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your year 9 maths lesson on: Calculating theoretical probabilities from probability tree diagrams (one event), 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.
We use learning cycles to break down learning into key concepts or ideas linked to the learning outcome. Each learning cycle features explanations with checks for understanding and practice tasks with feedback. All of this is found in our slide decks, ready for you to download and edit. The practice tasks are also available as printable worksheets and some lessons have additional materials with extra material you might need for teaching the lesson.
The assessment exit quiz will test your pupils' understanding of the key learning points.
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Explore more key stage 3 maths lessons from the Probability: theoretical probabilities unit, dive into the full secondary maths curriculum, or learn more about lesson planning.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.In a fair six-sided die, what is the probability of rolling a 3 and getting a head in a single toss of a fair coin?
Q2.What is the probability that this spinner will land on R?
Q3.A coin is flipped twice. Complete the sample space ξ = {HH, HT, , TT}
Q4.Andy tells his friend that this spinner is fair and that they have an equal chance of winning or losing. Is he right?
Q5.Sam thinks that if you place six consecutive whole numbers on each segment of this spinner, you will always have an equal chance of spinning an odd or an even number. Is Sam correct?
Q6.When rolling a fair six sided die, which event is more likely to occur?
Assessment exit quiz
6 Questions
Q1.What does a probability tree show?
Q2.Calculate the probability of event (A) in a probability tree if its branches have probabilities $$\frac{1}{4}$$, $$\frac{1}{3}$$, and (A)
Q3.In a probability tree, each branch shows a possible outcome along with the of that outcome happening.
Q4.If a probability tree has three branches with two branches having probabilities $$\frac{1}{5}$$ and $$\frac{2}{5}$$, what is the probability of the third outcome?
Q5.If a two branched probability tree has a branch with probability $$\frac{1}{5}$$, what is the probability of the complementary event?
Q6.in a probability tree, branches coming from the same root should all sum to what?