Lesson 67 - Related Events

A list of all possible (non-overlapping) outcomes of an experiment is called a sample space

Example 1:
One bill is randomly selected from the pot
a) Sample space:
   $0, $5, $10
b) What is the probability that the $5 bill is selected?
P(5)= 1/3

Related Events:
Complement- Opposite
The event that A does not occur is the complement of event A, and is denoted  A(with line on top)
*note: P(A) + P(A)*with line on top = 1

A and B
The event that both A and B occur is denoted by A and B

A or B
The event that A or B occurs (or both) is denoted by A or B

Example 2:
If each of the 13 outcomes in the sample space is equally likely, find:
Sample Space:

P(A)= 4/13 = 30%                              P(B)= 5/13
P(not A)= 9/13= 70%                         P(notB)= 8/13
P(A and B)= 1/13                               P(A or B)= 4/13 + 5/13 - 1/13 = 8 /13