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. 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, for example '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'
1 · Read
To order chances, compare the part of each set that matches the event with the whole set. If the totals match, the larger matching count is more likely. If totals differ, compare the shares, not just the counts. Then place events from least likely to most likely.
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.
An event is closer to certain when its share of possible outcomes is larger. A share near half is closer to even chance. A small share is closer to impossible. Compare the share with the whole set before ordering events.
To order likelihoods, compare how many ways each event can happen: more of one outcome means closer to certain, less means closer to impossible.
Linked YouTube video: 'Basic Probability | Is It Equal, Likely, Unlikely, Certain, or Impossible?' by Turtlediary; the video belongs to its channel, and only the link record was curated for os-taxonomy. The six extra practice questions were written for os-taxonomy. This file has no readings or flashcards.
2 · Watch
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