1. is the measure of how likely an event is (written as a ratio)
Probability
is the measure of how likely an event is (written as a ratio)

2. Probability of an event
The number of ways the event can occur divided by the total number of possible outcomes
P(A) = The number of ways an event can occur
Total number of possible outcomes

3. Example#1:
You roll a six-sided die whose sides are numbered from 1 through 6.
a) What is the probability of rolling an ODD number?
P(odd) =

4. P(“t”) = b) What is the probability of rolling
a number that starts with the
letter “t”?
P(“t”) =

5. Example #2: A jar contains 6 red, 5 green, 8 blue and 3 yellow marbles.
P(red) =
P(green) = P(blue) = P(yellow) =

6. Example#2: A jar contains 6 red, 5 green, 8 blue and 3 yellow marbles.
P(orange) =

7. Example #3: A deck of cards contains 52 cards made up of 4 different suits – Hearts, Diamonds, Spades, and Clubs. a) What is the probability of drawing a heart?

8. b) What is the probability of drawing a 3
b) What is the probability of drawing a 3? c) What is the probability of drawing a face card?

9. Practice #4 The table gives the handedness and eyedness of a randomly selected group of 100 people.
Right-Eyed
Left-Eyed
Right-Handed 57 31
Left-Handed 6
What is the probability of getting a left-handed person?

10. Practice #4 The table gives the handedness and eyedness of a randomly selected group of 100 people.
Right-Eyed
Left-Eyed
Right-Handed 57 31
Left-Handed 6
What is the probability of getting someone who is left-eyed?

11. Practice #4 The table gives the handedness and eyedness of a randomly selected group of 100 people.
Right-Eyed
Left-Eyed
Right-Handed 57 31
Left-Handed 6
What is the probability of getting someone who is left-handed and is also left-eyed?

12. Practice #4 The table gives the handedness and eyedness of a randomly selected group of 100 people.
Right-Eyed
Left-Eyed
Right-Handed 57 31
Left-Handed 6
What is the probability of getting someone who is right-handed and is also right-eyed?

13. Practice #5 The chart shows favorite subjects of students based on their gender.
Math
Science
English SS
Male 46 42 13 25
Female 12 21 45 36
What is the probability that a randomly chosen student likes Social Studies the most?

14. Practice #5 The chart shows favorite subjects of students based on their gender.
Math
Science
English SS
Male 46 42 13 25
Female 12 21 45 36
What is the probability that a randomly chosen student is female?

15. Practice #5 The chart shows favorite subjects of students based on their gender.
Math
Science
English SS
Male 46 42 13 25
Female 12 21 45 36
What is the probability that a randomly chosen student both likes science and is a male?

16. Practice #5 The chart shows favorite subjects of students based on their gender.
Math
Science
English SS
Male 46 42 13 25
Female 12 21 45 36
d) What is the probability that a randomly chosen student likes social studies and is a female?

17. Classwork!

18. Probability Tables

19. A Little Vocabulary Athletics Music/Arts SGA Other Total Male
Athletics
Music/Arts
SGA
Other
Total
Male
Male total
Female
Female total
Athletics total
Music/arts total
SGA total
Other total
Table total

20. Joint Probability

21. Marginal Probability

22. Conditional Probability

23. Example 1
Using the table below, what is the joint probability of a female that is involved in SGA?
0/30 = 0%
Athletics
Music/Arts
SGA
Other
Total
Male 10 5 1 2 18
Female 6 12 15 11 3 30

24. Example 2
Using the table below, what is the marginal probability of choosing someone who is involved with athletics?
15/30 = 50%
Athletics
Music/Arts
SGA
Other
Total
Male 10 5 1 2 18
Female 6 12 15 11 3 30

25. Example 3
Using the table below, what is the conditional probability given that a person is male, that they are involved in Music/Arts?
5/18 = 28%
Athletics
Music/Arts
SGA
Other
Total
Male 10 5 1 2 18
Female 6 12 15 11 3 30

26. Classwork
Task Handout

27. Classwork/Homework
Back of Task/Handout