1. Probability Rules and Models

2. Probability Model A probability model describes the possible outcomes…
And it says how to assign each of the events.
Marital Status
Never Married
Married
Widowed
Divorced
Probability
0.386
0.555
0.004
0.055

3. Probability Rules All probabilities must total 1.
If an event has probability 0, that means event never occurs.
If an event has probability 1, that means the event always occurs.
Probability Rules

4. The probability that something doesn’t happen is equal to 1 minus the probability that it does happen:
P(E’) = 1 – P(E)
If two events are mutually exclusive, the probability that either one happens is P(A) + P(B)…this is the Addition Rule
(There is more to this rule…we will discuss this on Monday)
More Rules…

5. Other Rules We will be discussing these next week:
More about the Addition Rule
Multiplication Rule
Conditional Probability
Other Rules

6. Each group must come up with a probability model to put on the board.
You will be brought to the board in random order.
If another group already had your topic, you need to do a different one—have a back up.
Now…

7. And here’s the Ch. 7 Assignment…