Year 11
Higher
Year 11
Higher
Calculate probabilities of independent events
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Lesson details
Key learning points
- In this lesson, we will learn how to calculate probabilities of outcomes for independent events from tree diagrams
Licence
This content is made available by Oak National Academy Limited and its partners and licensed under Oak’s terms & conditions (Collection 1), except where otherwise stated.
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3 Questions
Q1.
Here is the first branch of a probability tree diagram.
B
C
D
Q2.
Here is the first branch of a different probability tree diagram. What should the missing probability be?
0.41
0.82
18
Q3.
This tree diagram shows Amir taking red and blue counters from a jar. He replaces the counter after he has picked one up.
A
B
D
3 Questions
Q1.
For the probability tree shown, which calculation will find the probability of red followed by blue happening?
0.2 + 0.2
0.2 x 0.2
0.8 x 0.8
Q2.
The probability that Amy and Joe win a game of chess is shown in the tree diagram. Work out the probability that over 2 games Amy wins twice.
0.49
0.6
0.9
Q3.
James draws this probability tree diagram to help him calculate probabilities of taking sweets from a bag. What assumptions has James made when completing this probability tree?
All probabilities add to 1 on each branch.
It doesn’t matter if he eats the first sweet he takes.