Likelihood.

Wala: Likelihood.

L.O: Recognise that some outcomes are equally likely to happen and some are more or less likely to happen.

​STARTER.

​ Probability games (15 minutes)

Resources: A large dice.

Description: Put the class into two teams, for example Team A and Team B. Tell the learners that you will roll the large dice. If the dice lands on 1, 2 or 3, Team A scores a point. If the dice lands on 4 neither team scores a point. If the dice lands on 5 or 6, Team B scores a point. Roll the dice and keep score of the points. The first team to score 20 points wins.

​Class Discussion.

​ After about 12 points have been scored ask:

 • Are both teams equally likely to score a point?

• Are both teams equally likely to win (score 20 points first)?

• Which team is more likely to win?

• Does that mean that they will always win?

• How can we change the game so that both teams are equally likely to win?

Repeat the game using one of the learner’s suggestions for how to change the game so that both teams are equally likely to win.

​Main Activity.

​ Equally-likely outcomes.

Learning intention: Recognise when two outcomes are equally likely.

Resources: Likelihood scale, Resource sheet 8A.

​Description: Show learners the likelihood scale

Ask learners to point to the place on the line where they would put rolling a 1 on a 6-sided dice. Repeat with the numbers 2 to 6.

​Explanation.

​ They should point to the same place in the ‘unlikely’ region of the probability line for each number.

Not only does each number on the dice have an ‘unlikely’ chance, they all have the same likelihood of 1 chance out of 6.

We say that these outcomes are ‘equally likely’.

​Group Work.

​Give each pair of learners a copy of Resource sheet 8A. Tell them to cut along the lines then group the outcomes on the sheet to show which outcomes they believe are equally likely (A flipped coin..., The next baby ...).

1. Discuss and then write six more outcomes that are equally likely to some of the outcomes they have already grouped.

2. Write at least one statement each that is certain, impossible or has an even chance.

​Class Discussion.

​ Sometimes people confuse the terms ‘even chance’ and ‘equally likely’. Tell learners to work with their partner to write a definition for ‘even chance’ and a definition for ‘equally likely’. Display accurate and clear definitions in the class for learners to refer to.

​ANSWER.

​

• Even chance: There is the same chance that an outcome will happen or will not happen.

• Equally likely: Outcomes that have the same chance of happening.

​

​INDIVIDUAL WORK.

​

Learners book

page 92,

number 3 to 4