Probability quantifies how likely an event is on a scale from 0 to 1, or equivalently from 0% to 100%, using equally likely outcomes, simple sample spaces, and experimental results represented as fractions, decimals, or percents. Learners compare probabilities to justify choices, distinguish greater likelihood from certainty, and recognize that a more probable outcome is not guaranteed; complex dependent events, expected value, and formal statistical decision analysis are beyond this scope.
Probability tells how likely an event is.
For equally likely outcomes, use:
To make a decision, find and compare the probabilities. Choose the option with the greater probability if you want the event to be more likely.
Example: You can choose one of two games. In each game, you win if you get blue.
Which game should you choose to make winning more likely?
Step 1: Find the probability of winning Game A.
There are marbles total, and are blue.
Step 2: Find the probability of winning Game B.
There are equal sections, and are blue.
Step 3: Compare the probabilities.
Game B has the greater probability of winning, so Game B is the better choice if you want to make winning more likely.
Remember: Game B is more likely to win, but winning is not certain. You could still land on a non-blue section.
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