1. Chapter 5: Elementary Probability Theory
5.1 – What is Probability
5.2 – Some Probability Rules – Compound Events
5.3 – Trees and Counting Techniques

2. “How Often Do Lie Detectors Lie?”
Focus Problem
“How Often Do Lie Detectors Lie?”
Read page 159=160 in text book

3. 5.1 – What is Probability?
Numerical measure between 0 and 1 that describes the likelihood that an event will occur.
0 ≤ P(A) ≤ 1
P(A) = Probability of “event A”
If P(A) = 0, the event is certain NOT to occur
If P(A) = 1, the event is certain to occur

4. Probability Assignments
Intuition: incorporates past experience, judgment, or opinion to estimate the likelihood of an event.
Relative Frequency: uses the formula,
𝑓 𝑛
where f is the frequency of the event occurrence in a sample of n observations.
Equally Likely Outcomes: uses the formula,
Number of outcomes favorable to an event Total number of outcomes

5. Guided Exercise #1 As whole group, turn to page 161-162
Look-over answers
Whole group clarification

6. Vocabulary
Law of Large Numbers: as the sample size increases and increases, the relative frequencies of the outcomes get closer and closer to the theoretical (or actual) probability value.
Statistical Experiment/Obsevation: any random activity that results in a definite outcome.
Event: a collection of one or more outcomes of a statistical experiment/observation.
Simple Event: only one outcome
Sample Space: set of all simple events of an experiment/observation.
Sum of the probabilities of all simple events in a sample space must = 1

7. Guided Exercise #2 As whole group, turn to page 163-164 Cover answers
Whole group clarification

8. More Vocabulary
Complement of Event A (Ac): event that “A” does not occur.
P(A) + P(Ac) = 1
P(Ac) = 1 – P(A)

9. Guided Exercise #3 As whole group, turn to page 165 Cover answers
Whole group clarification

10. Checkpoint Assign probabilities to events
Explain how the law of large numbers relates to relative frequencies
Apply basic rules of probability in everyday life.
Explain relationship between statistics and probability

11. Homework Read Pages 160-166 Do Problems
Take notes on what we have not covered
Do Problems
Page (1-11) odds
Check odds in back of book
Read and preload 5.2 information
Notes/vocab