Formula
Probability is the favorable count divided by the possible count:
Probability = favorable outcomes / possible outcomes
The result is shown as a percent.
Assumptions
- Every outcome is equally likely.
- Favorable outcomes are part of the possible outcomes.
Worked example
3 favorable outcomes out of 8 is a probability of 37.50%.
Input definitions
- Favorable outcomes
- The outcomes you are counting as a success.
- Possible outcomes
- The full set of equally likely outcomes.
Limitations
This does not combine independent events or use a probability distribution.
Questions
Can the favorable count be zero?
Yes. The probability is 0%.
What if the outcomes are not equally likely?
This formula does not apply. It assumes each outcome has the same chance.