Ordering Likelihoods
Compare the likelihood of different events and order them from least to most likely — including situations with unequal outcomes such as a bag with more of one colour than another, or a spinner with sections of different sizes — and explain reasoning using informal language
What a learner can do afterwards
- Order four or more events from least likely to most likely and justify each placement
- Compare likelihoods when outcomes are not equally likely — e.g. 'Drawing red from a bag with 7 red and 3 blue is more likely than drawing blue'
- Explain why some events are closer to 'even chance' and others are closer to 'certain' or 'impossible'
The lesson
You already know words like impossible, unlikely, even chance, likely, and certain. Now you can use those words to put several events in order, from the one least likely to happen to the one most likely. To order events, look at how many ways each one can happen out of the total.
Priya lines up four spinners. One is mostly blue, one is half blue and half yellow, one is mostly yellow, and one is all yellow. She orders them from least likely to land on blue to most likely: all yellow, mostly yellow, half-and-half, mostly blue. She checks each spinner by comparing how much blue it has.
When you order events, check how close each one is to even chance, about half and half, compared with certain, almost all one outcome, or impossible, almost none of that outcome. The more one outcome outnumbers the rest, the closer it is to certain.
To order likelihoods, compare how many ways each event can happen: more of one outcome means closer to certain, less means closer to impossible.
Watch it
Where it sits
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Where this leads
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8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.