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Year 9

Equally likely outcomes

I can state when outcomes will be equally likely.

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New
New
Year 9

Equally likely outcomes

I can state when outcomes will be equally likely.

Link copied to clipboard

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Lesson details

Key learning points

  1. A set of possible outcomes can be stated.
  2. Outcomes can be evaluated to decide how likely they are.
  3. Outcomes with the same likelihood can be identified.

Keywords

  • Outcome - An outcome is a result of a trial.

  • Likelihood - Likelihood describes the chance that a particular event will occur.

  • Trial - A trial is a single predefined test.

  • Sample space - A sample space is all the possible outcomes of a trial. A sample space diagram is a systematic way of producing a sample space.

Common misconception

Rolling a 6 on a dice is less likely to happen than rolling other numbers. Or ticket 001 is less likely to be drawn in a raffle than other tickets.

The random nature of picking a raffle or rolling a dice means all outcomes are equally likely as each other.


To help you plan your year 9 maths lesson on: Equally likely outcomes, download all teaching resources for free and adapt to suit your pupils' needs...

Ask pupils to design a their own single-trial game where the likelihoods of winning and losing are equal.
Teacher tip

Licence

This content is © Oak National Academy Limited (2025), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

Lesson video

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6 Questions

Q1.
Select all the numbers that are multiples of 3.
0.3
1
Correct answer: 3
Correct answer: 6
Correct answer: 9
Q2.
Select all the numbers that are factors of 3.
0.3
Correct answer: 1
Correct answer: 3
6
9
Q3.
What fraction of the circle is shaded?
An image in a quiz
$${1}\over{3}$$
$${3}\over{7}$$
Correct answer: $${3}\over{10}$$
$${3}\over{13}$$
Q4.
In which diagrams is half of the circle shaded?
An image in a quiz
Correct Answer: An image in a quiz
An image in a quiz
An image in a quiz
Correct Answer: An image in a quiz
An image in a quiz
Q5.
Jun wants to shade in $${1}\over{3}$$ of this whole circle. Jun should shade in sectors of the circle.
An image in a quiz
Correct Answer: 4, four, four sectors, 4 sectors
Q6.
Match each letter to the fraction of the circle that is labelled with that letter.
An image in a quiz
Correct Answer:a,$${1}\over{4}$$

$${1}\over{4}$$

Correct Answer:b,$${1}\over{3}$$

$${1}\over{3}$$

Correct Answer:c,$${5}\over{12}$$

$${5}\over{12}$$

6 Questions

Q1.
Match each key words with its definition.
Correct Answer:trial,a single predefined test

a single predefined test

Correct Answer:outcome,a result of a trial

a result of a trial

Correct Answer:sample space,all the possible outcomes of a trial

all the possible outcomes of a trial

Correct Answer:likelihood,describes the chance that a particular event will occur

describes the chance that a particular event will occur

Q2.
Complete the following sample space for the outcomes of the spinner. ξ = {A, I, L, R, }.
An image in a quiz
Correct Answer: T
Q3.
In which spinners are the outcomes 'win' and 'lose' equally likely?
An image in a quiz
Correct Answer: An image in a quiz
An image in a quiz
Correct Answer: An image in a quiz
An image in a quiz
An image in a quiz
Q4.
Which outcomes are equally likely in this spinner?
An image in a quiz
Correct answer: A and B
A and C
B and C
Q5.
In which spinners are all the outcomes equally likely?
Correct Answer: An image in a quiz
An image in a quiz
An image in a quiz
An image in a quiz
Correct Answer: An image in a quiz
An image in a quiz
Q6.
A regular six-sided dice is rolled once. In which sample space are the outcomes equally likely?
ξ = {factor of 6, not a factor of 6}
ξ = {multiple of 3, not a multiple of 3}
Correct answer: ξ = {odd, even}
ξ = {square number, not a square number}