1. Introduction to Probability
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2. Warm Up
Write each fraction as a percent.
1). 𝟏 𝟒 2). 𝟐 𝟓 3). 𝟑 𝟖
4). 𝟐 𝟑 5). 𝟏 𝟏𝟎 ). 𝟗𝟎 𝟏𝟎𝟎
25%
40%
37.5%
67%
10%
90%

3. Probability of an event, written P(event), is the measure of how likely an event is to occur.
What is the probability of :
-picking a pink counter? P(pink)
-picking a green counter? P(green)
-picking a pink or yellow counter?
P(pink or yellow)
2/9
3/9 or 1/3
3/9 or 1/3

4. Determining the Likelihood of an Event

5. As likely as not. impossible likely certain
Practice
Determine whether each event is impossible, unlikely, as likely as not, likely or certain.
As likely as not.
1).Rolling an odd number on a number cube.
2).Rolling a 7 on a number cube.
3).Rolling a number greater than 2 on a number cube.
4).Rolling a 1, 2, 3, 4, 5, or 6 on a number cube.
impossible
likely
certain

6. P(event) + P(complement) = 1
The complement of an event is the set of all outcomes that are not the event.
The sum of the probabilities of an event and its complement is 1.
P(event) + P(complement) = 1

7. Find the following probabilities: 1). P(blue) 2). P(not blue)
Practice
Find the following probabilities:
1). P(blue)
2). P(not blue)
3). P(green)
4). P(not green)
2/6 or 1/3
4/6 or 2/3
1/6
5/6

8. Closure
Describe something that has a probability of 100% and has a probability of 0%.

9. Simple Events
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10. Warm Up
Determine whether each event is impossible, unlikely, as likely as not, likely or certain.
1). Rolling a 5 on a number cube.
2). Rolling an odd number on a number cube.
3). Picking a blue cube from a bag that contains 8 green, 6 red, and 3 pink cubes.
4). Tossing a coin and getting a head or tails.
unlikely
#2 As likely as not
#3 impossible
#4 certain

11. A simple event has a single outcome.
The probability of an event is how likely an event is to occur. You can write the probability as a fraction, decimal or percent.
P(event) = 𝒏𝒖𝒎𝒃𝒆𝒓 𝒐𝒇 𝒇𝒂𝒗𝒐𝒓𝒂𝒃𝒍𝒆 𝒐𝒖𝒕𝒄𝒐𝒎𝒆𝒔 𝒏𝒖𝒎𝒃𝒆𝒓 𝒐𝒇 𝒑𝒐𝒔𝒔𝒊𝒃𝒍𝒆 𝒐𝒖𝒕𝒄𝒐𝒎𝒆𝒔
Means the probability of an event.

12. E
Examples:
You roll one number cube. Give the following probabilities.Write as a fraction, decimal and percent.
1/6, 0.167, 16.7%
(answer is rounded)
1). P(rolling a five )
2). P( rolling an even number)
3). P( not rolling a 7)
½, 0.50, 50%
1, 1, 100%

13. Practice What is the probability of: 1). P(circle) 2). P(pink circle)
Write each probability as a percent and a fraction.
What is the probability of:
1). P(circle)
2). P(pink circle)
3). P(blue shape)
4). P(black circle)
5). P(stars and circles)
6). P(not stars)
7). P(not white)
2/10 or 1/5 or 20%
1/10 or 10%
2/10 0r 1/5 or 20%
0 or 0%
6/10 or 3/5 or 60%
6/10 or 3/5 or 60%
1 or 100%

14. Closure
Make up 2 probability problems using the figures below.

15. Experimental and Theoretical Probability
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16. 1 3 2 4 1 1 4 2 Warm Up 1). P(2) 2). P(1) 3). P( odd number)
Find the probability of each. Write your answer as a decimal, fraction and
percent.
1). P(2)
2). P(1)
3). P( odd number)
4). P(not even)
5). P(6) 1 3 2 4
2/8 or ¼, 0.25, 25% 1 1
3/8, 0.375, 37.5% 4 2
4/8 or ½,0.50, 50%
4/8 or ½,0.50, 50%
0, 0, 0%

17. Flippable

18. The more trials you have the more accurate the estimate is.
Experimental Probability- a way of estimating the probability of an event.
Experimental Probability = 𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑡𝑖𝑚𝑒𝑠 𝑎𝑛 𝑒𝑣𝑒𝑛𝑡 ℎ𝑎𝑝𝑝𝑒𝑛𝑠 𝑡𝑜𝑡𝑎𝑙 𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑡𝑖𝑚𝑒𝑠 𝑡ℎ𝑒 𝑎𝑐𝑡𝑖𝑣𝑖𝑡𝑦 𝑖𝑠 𝑝𝑒𝑟𝑓𝑜𝑟𝑚𝑒𝑑
The more trials you have the more accurate the estimate is.

19. Example 1:
John rolled a number cube 15 times and rolled a two 6 of those times. What is the experimental probability of rolling a two? Write your answer as a fraction and a percent.
6 out of 15 or 2/5, 40%
Example 2:
Kim made 10 out of 15 shots in basketball. What is the experimental probability she will make a basket? Write your answer as a fraction and a percent.
10/15 or 2/3, 67%

20. Theoretical Probability is the likeliness of an event happening based on all of the possible outcomes.
Theoretical Probability= 𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑓𝑎𝑣𝑜𝑟𝑎𝑏𝑙𝑒 𝑜𝑢𝑡𝑐𝑜𝑚𝑒𝑠 𝑡𝑜𝑡𝑎𝑙 𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑝𝑜𝑠𝑠𝑖𝑏𝑙𝑒 𝑜𝑢𝑡𝑐𝑜𝑚𝑒𝑠

21. a). Picking a blue triangle.
Examples:
Find the probability of each problem. Write your answer as a fraction and a percent.
a). Picking a blue triangle.
b). Picking a circle or square
c). Not picking a circle.
2/8 or ¼, 25%
5/8, 62.5%
6/8 or ¾, 75%

22. Practice
Write the answer as a fraction and a percent.
1). Jan tossed a coin 50 times and got a head 20 times. What is the experimental probability? What is the theoretical probability?
2). Stephen hit a baseball 10 out of 30 times. What is the experimental probability that he will hit the ball on the next try?
3). Henry rolled a number cube 100 times and got an even number 45 times. What is the experimental probability? What is the theoretical probability?
2/5,40% ½, 50%
1/3, 33%
9/20, 45% ½, 50%

23. Closure
How are experimental and theoretical probability alike? Different?