Unit E: Statistics and Probability

Chapter 2: Probability

Probability is the chance than an outcome will occur.
An outcome is a possible result that can be favourable or unfavourable.
The formula for probability is

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The higher the probability, the more likely the outcome will occur.
If two events are equally likely, they have the same chance of occurring.
A probability of 0 or 0% indicates that it is impossible for the outcome to occur.
A probability of 1 or 100% indicates that the outcome will definitely occur.

Probability can be written as a fraction, decimal, percent, ratio, or statement.
When written in decimal form, the probability must be between 0 and 1 and stated to three decimal places.
When written as a percent, the probability must be between 0% and 100% and state to one decimal place.