1. Probability
Vocabulary

2. Probability
Kelly is playing a game using 8 number cards numbered Kelly scores a point if she selects a card that has a 7 or greater. 1 2 3 4 5 6 7 8

3. Probability Experiment
Probability experiment- an experiment where the exact results cannot be predicted.
Example: Blindly selecting cards in Kelly’s game

4. Outcome- a possible result in a probability experiment.
Example: Any of the numbers (1-8) on the cards in Kelly’s game.

5. Sample Space
Sample space- a set of all possible outcomes in a probability experiment.
Example: A sample space for this experiment is 1, 2, 3, 4, 5, 6, 7, & 8 (the numbers on the card).

6. Event- a set of one or more outcomes in a probability experiment.
Example: Selecting an even number or selecting a specific number.

7. Probability
Probability- a number greater than or equal to 0 and less than or equal to 1, showing the chance of an event happening.
The probability (P) of an event (A) is…
Number of favorable outcomes
P(A) =
Number of possible outcomes
Example: Kelly is hoping to select a 7 or greater.
This means the favorable outcomes are selecting a 7 or 8.
Possible outcomes are 1, 2, 3, 4, 5, 6, 7, or 8
Selecting a 7 or 8 2 1
P(7 or greater) = = =
Number of possible outcomes 8 4

8. Likely- an event will probably happen.
Since there are 4 blue sections and only 1 red section, it is likely that this spinner will land on blue.

9. Spinning a yellow or a green are equally likely.
Equally Likely- an event that is just as likely to happen as not to happen.
Spinning a yellow or a green are equally likely.

10. Unlikely Unlikely- an event that probably will not happen.
Since green is only 1 of 11 sections, spinning a green is unlikely.

11. Impossible Impossible- an event that cannot happen.
The possibility of spinning a yellow is impossible.

12. Certain Certain- an event will definitely happen.
The possibility of spinning a blue is certain.

13. P(purple) Probability Ratio Fraction Decimal Percent 1:8 ⅛ 0.125 12.5%
Probability can be expressed in four different ways: ratio, fraction, decimal, & percent. 1 2 3 4 8 7 6 5
P(purple)
Ratio
Fraction
Decimal
Percent
1:8 ⅛
0.125
12.5%

14. P(4 or 5) Probability Ratio Fraction Decimal Percent 2:8 ¼ 0.25 25%
Probability can be expressed in four different ways: ratio, fraction, decimal, & percent. 1 2 3 4 8 7 6 5
P(4 or 5)
Ratio
Fraction
Decimal
Percent
2:8
0.25
25%

15. P(even #) Probability Ratio Fraction Decimal Percent 4:8 ½ 0.5 50%
Probability can be expressed in four different ways: ratio, fraction, decimal, & percent. 1 2 3 4 8 7 6 5
P(even #)
Ratio
Fraction
Decimal
Percent
4:8
0.5
50%

16. P(# greater than 3) Probability Ratio Fraction Decimal Percent 5:8 ⅝
Probability can be expressed in four different ways: ratio, fraction, decimal, & percent. 1 2 3 4 8 7 6 5
P(# greater than 3)
Ratio
Fraction
Decimal
Percent
5:8 ⅝
0.625
62.5%

17. P(blue shirt) Probability Ratio Fraction Decimal Percent 8:20 0.40 40%
Probability can be expressed in four different ways: ratio, fraction, decimal, & percent.
Paul’s Closet
Color
# of Shirts
Green 3
Red 4
White 5
Blue 8
Total 20
P(blue shirt)
Ratio
Fraction
Decimal
Percent
8:20 2 5
0.40
40%

18. P(green or red) Probability Ratio Fraction Decimal Percent 7:20 0.35
Probability can be expressed in four different ways: ratio, fraction, decimal, & percent.
Paul’s Closet
Color
# of Shirts
Green 3
Red 4
White 5
Blue 8
Total 20
P(green or red)
Ratio
Fraction
Decimal
Percent
7:20 7 20
0.35
35%

19. Probability P(any color, but white) Ratio Fraction Decimal Percent
Probability can be expressed in four different ways: ratio, fraction, decimal, & percent.
Paul’s Closet
Color
# of Shirts
Green 3
Red 4
White 5
Blue 8
Total 20
P(any color, but white)
Ratio
Fraction
Decimal
Percent
15:20
0.75
75%

20. P(pink) Probability Ratio Fraction Decimal Percent 0:20 0.00 0%
Probability can be expressed in four different ways: ratio, fraction, decimal, & percent.
Paul’s Closet
Color
# of Shirts
Green 3
Red 4
White 5
Blue 8
Total 20
P(pink)
Ratio
Fraction
Decimal
Percent
0:20 20
0.00 0%