What is likelihood?
Likelihood tells us how likely an event is to happen. We use everyday words to describe it: certain, likely, even chance, unlikely, and impossible. Think about how many outcomes give what you want compared to all the possible outcomes.
Key idea
Certain = will definitely happen. Impossible = will never happen. Even chance = equally likely to happen or not. Likely / unlikely = probably will / probably will not.
Worked example
Worked example
A normal die has the numbers 1 to 6.
Rolling a number from 1 to 6 is certain.
Rolling a 7 is impossible.
Rolling an even number (2, 4, 6) is an even chance, because 3 of the 6 numbers are even.
Now think of a bag with 9 red balls and 1 blue ball. Drawing red is likely and drawing blue is unlikely, because there are far more red balls than blue ones.
Remember
- Certain will always happen.
- Impossible will never happen.
- Even chance means half and half.
- The more of a colour in a bag, the more likely you draw it.