What is simple probability?

Simple Probability

Simple probability is the most basic form of probability.
Simple probability describes the likelihood of a single event happening when all possible outcomes are equally likely.
Probability can be described using a ratio (fraction), decimal or percent.

How do we calculate simple probability?

​The probability of an event is calculated using the formula:







Favorable outcomes: the results you want, the desired outcome

Total outcomes: ALL the possible results (outcomes) that could happen

Note: Probability can be written as a fraction (in simplest form), a decimal or a percent.

Example 1:

Example 2:

Here are some more simple probability practice questions.
Remember to simplify your fractions!

Complement

​In probability, what does the complement represent?

The complement of an event is “everything that does not happen.”
If an event is called A, then the complement of A means:

All the outcomes where A does NOT happen.

​P(odd) = probability the outcome is odd

​What is the probability of rolling an odd number on a number cube?

P′(odd) = probability the outcome is NOT odd

​What is the probability of NOT rolling an odd number on a number cube?

You can write the complement three different ways:
P′(odd) = P(odd′) = P(not odd)

​In probability, the little prime symbol ′ (apostrophe) means “complement.”

​How do we write the complement in probability?

​P(event) + P′(event) = 1

In probability ....

The End ... Well Done!!!