​Sample Space

• ​A sample space is a list of all possible outcomes

• ​ The sample space from rolling a regular die is 1,2,3,4,5,6

• ​ Pr (1) = 1/6 as there is only 1 successful outcome from all possible outcomes

• ​ Pr (even) = ?

​What is Probability?

• An event is something that happens

• ​The probability of an event is the likelihood, or chance of that event happening.

• ​ A probability is a number which is between 0 and 1.

• ​ Probability is labeled as Pr(event) and may be written as decimals, fractions or percentages.

​Complements

• ​ An event may happen or may not happen

• ​Pr (event occuring) + Pr (event not occuring) = 1

• Pr (event not occuring) = 1 - ​​Pr (event occuring)

• ​Each outcome is called the complement of the other.

​Learning Task