Probability
The likelihood scale
We describe how likely something is with words on a likelihood scale: impossible, unlikely, even chance, likely and certain.
The scale
ā¢ Impossible ā it cannot happen. ā¢ Unlikely ā a small chance. ā¢ Even chance ā just as likely to happen as not. ā¢ Likely ā a good chance. ā¢ Certain ā it will definitely happen.
Worked examples
Rolling a 5
- A 6-sided dice has 6 outcomes.
- Only 1 of them is a 5.
Answer: Rolling a 5 is unlikely.
Flipping heads
- A coin has 2 equally likely outcomes.
- One of them is heads.
Answer: Getting heads is an even chance.
Where you see this in real life
- Deciding if it is likely to rain from a weather forecast.
- Knowing it is certain the sun will set today.
- Understanding warning signs about risks.
Key words
- Likelihood
- How likely something is to happen.
- Impossible
- An event that cannot happen.
- Certain
- An event that will definitely happen.