1. Experimental Probability
11-2
Experimental Probability
Course 1
Warm Up
Problem of the Day
Lesson Presentation

2. Experimental Probability
Course 1
11-2
Experimental Probability
Warm Up
Write impossible, unlikely, equally likely, likely, or certain to describe each event.
1. A particular person’s birthday falls on the first of a month.
2. You roll an odd number on a fair number cube.
3. There is a 0.14 probability of picking the winning ticket. Write this as a fraction and as a percent.
unlikely
equally likely
, 14% 7 50 __

3. Experimental Probability
Course 1
11-2
Experimental Probability
Problem of the Day
Max picks a letter out of this problem at random. What is the probability that the letter is in the first half of the alphabet? 57
101
___

4. Experimental Probability
Course 1
11-2
Experimental Probability
Learn to find the experimental probability of an event.

5. Insert Lesson Title Here
Course 1
11-2
Experimental Probability
Insert Lesson Title Here
Vocabulary
experiment
outcome
sample space
experimental probability

6. Experimental Probability
Course 1
11-2
Experimental Probability
An experiment is an activity involving chance that can have different results. Flipping a coin and rolling a number cube are examples of experiments.
The different results that can occur are called outcomes of the experiment. If you are flipping a coin, heads is one possible outcome.
The sample space of an experiment is the set of all possible outcomes. You can use {} to show sample spaces. When a coin is being flipped, {heads, tails} is the sample space.

7. Additional Example 1A: Identifying Outcomes and Sample Spaces
Course 1
11-2
Experimental Probability
Additional Example 1A: Identifying Outcomes and Sample Spaces
For each experiment, identify the outcome shown and the sample space.
A. Spinning two spinners
outcome shown: B1
sample space: {A1, A2, B1, B2}

8. Additional Example 1B: Identifying Outcomes and Sample Spaces
Course 1
11-2
Experimental Probability
Additional Example 1B: Identifying Outcomes and Sample Spaces
For each experiment, identify the outcome shown and the sample space.
B. Spinning a spinner
outcome shown: green
sample space: {red, purple, green}

9. Experimental Probability
Course 1
11-2
Experimental Probability
Try This: Example 1A
For each experiment, identify the outcome shown and the sample space.
A. Spinning two spinners C D 3 4
outcome shown: C3
sample space: {C3, C4, D3, D4}

10. Experimental Probability
Course 1
11-2
Experimental Probability
Try This: Example 1B
For each experiment, identify the outcome shown and the sample space.
B. Spinning a spinner
outcome shown: blue
sample space: {blue, orange, green}

11. Experimental Probability
Course 1
11-2
Experimental Probability
Performing an experiment is one way to estimate the probability of an event. If an experiment is repeated many times, the experimental probability of an event is the ratio of the number of times the event occurs to the total number of times the experiment is performed.

12. Experimental Probability
Course 1
11-2
Experimental Probability
Writing Math
The probability of an event can be written as P(event). P(blue) means “the probability that blue will be the outcome.”

13. Additional Example 2: Finding Experimental Probability
Course 1
11-2
Experimental Probability
Additional Example 2: Finding Experimental Probability
For one month, Mr. Crowe recorded the time at which his train arrived. He organized his results in a frequency table.
Time
6:49-6:52
6:53-6:56
6:57-7:00
Frequency 7 8 5

14. Additional Example 2A Continued
Course 1
11-2
Experimental Probability
Additional Example 2A Continued
A. Find the experimental probability that the train will arrive before 6:57.
Before 6:57 includes 6:49-6:52 and 6:53-6:56.
P(before 6:57) 
number of times the event occurs
total number of trials
___________________________ =
7 + 8 20
_____ = 15 20
___ = 3 4 __

15. Additional Example 2B: Finding Experimental Probability
Course 1
11-2
Experimental Probability
Additional Example 2B: Finding Experimental Probability
B. Find the experimental probability that the train will arrive between 6:53 and 6:56.
P(between 6:53 and 6:56) 
number of times the event occurs
total number of trials
___________________________ = 8 20
___ = 2 5 __

16. Experimental Probability
Course 1
11-2
Experimental Probability
Try This: Example 2
For one month, Ms. Simons recorded the time at which her bus arrived. She organized her results in a frequency table.
Time
4:31-4:40
4:41-4:50
4:51-5:00
Frequency 4 8 12

17. Experimental Probability
Course 1
11-2
Experimental Probability
Try This: Example 2A
A. Find the experimental probability that the bus will arrive before 4:51.
Before 4:51 includes 4:31-4:40 and 4:41-4:50.
P(before 4:51) 
number of times the event occurs
total number of trials
___________________________ =
4 + 8 24
_____ = 12 24
___ = 1 2 __

18. Experimental Probability
Course 1
11-2
Experimental Probability
Try This: Example 2B
B. Find the experimental probability that the bus will arrive between 4:41 and 4:50.
P(between 4:41 and 4:50) 
number of times the event occurs
total number of trials
___________________________ = 8 24
___ = 1 3 __

19. Additional Example 3: Comparing Experimental Probabilities
Course 1
11-2
Experimental Probability
Additional Example 3: Comparing Experimental Probabilities
Erika tossed a cylinder 30 times and recorded whether it landed on one of its bases or on its side. Based on Erika’s experiment, which way is the cylinder more likely to land?
Outcome
On a base
On its side
Frequency
llll llll
llll llll llll llll l
Find the experimental probability of each outcome.

20. Additional Example 3 Continued
Course 1
11-2
Experimental Probability
Additional Example 3 Continued = 9 30
___
P(base) 
number of times the event occurs
total number of trials
___________________________ = 21 30
___
P(side) 
number of times the event occurs
total number of trials
___________________________ 9 30
___
< 21 30
___
Compare the probabilities.
It is more likely that the cylinder will land on its side.

21. Experimental Probability
Course 1
11-2
Experimental Probability
Try This: Example 3
Chad tossed a cylinder 25 times and recorded whether it landed on one of its bases or on its side. Based on Chads’s experiment, which way is the cylinder more likely to land?
Outcome
On a base
On its side
Frequency
llll
llll llll llll llll
Find the experimental probability of each outcome.

22. Try This: Example 3 Continued
Course 1
11-2
Experimental Probability
Try This: Example 3 Continued = 5 25
___
P(base) 
number of times the event occurs
total number of trials
___________________________ = 20 25
___
P(side) 
number of times the event occurs
total number of trials
___________________________ 5 25
___
< 20 25
___
Compare the probabilities.
It is more likely that the cylinder will land on its side.

23. Experimental Probability Insert Lesson Title Here
Course 1
11-2
Experimental Probability
Insert Lesson Title Here
Lesson Quiz: Part 1
1. The spinner below was spun. Identify the outcome shown and the sample space.
outcome: green; sample space: {red, blue, green, purple, yellow}

24. Experimental Probability Insert Lesson Title Here
Course 1
11-2
Experimental Probability
Insert Lesson Title Here
Lesson Quiz: Part 2
Sandra spun the spinner above several times and recorded the results in the table.
2. Find the experimental probability that the spinner will land on blue.
3. Find the experimental probability that the spinner will land on red.
4. Based on the experiment, on which color will the spinner most likely land? 2 9 __ 4 9 __
red