Probability measures how likely an event is, from 0 for impossible to 1 for certain. For equally likely outcomes it is the number of favorable outcomes divided by the total number of outcomes.
Math Dictionary / Probability
Probability
Probability measures how likely an event is to happen.
StatisticsGrade 6Grade 7Grade 8GEDSATACT
What it means
It is often written as favorable outcomes divided by total possible outcomes.
Also called: chance
Examples
| P(heads) = 1/2 for a fair coin |
| P(rolling a 3) = 1/6 |
| Probability ranges from 0 to 1 |
Common mistake
A probability cannot be less than 0 or greater than 1.
Try one
Question: What is the probability of choosing a vowel from A, B, C, D, E?
Show answer
There are 2 vowels out of 5 letters, so the probability is 2/5.