10-5 Experimental Probability
Do Now
Write the equivalent percent.
1.
30%
2.
25%
3.
20%
Write the equivalent fraction.
4. 10%
5. 40%
6. 35%
Write the equivalent decimal.
7. 50% 0.5
Holt Algebra 1
8.
0.2
9.
0.9
10-5 Experimental Probability
An experiment is an activity involving chance.
Each repetition or observation of an experiment is a
trial, and each possible result is an outcome. The
sample space of an experiment is the set of all
possible outcomes.
Holt Algebra 1
10-5 Experimental Probability
Example 1: Identifying Sample Spaces and Outcomes
Identify the sample space and the outcome
shown for each experiment.
A. Rolling a number cube
Sample space:{1, 2, 3, 4, 5, 6}
Outcome shown: 4
B. Spinning a spinner
Sample space:{red, green,
orange, purple}
Outcome shown: green
Holt Algebra 1
10-5 Experimental Probability
An event is an outcome or set of outcomes in an
experiment.
Probability is the measure of how likely an
event is to occur. Probabilities are written as
fractions or decimals from 0 to 1, or as percents
from 0% to 100%.
Holt Algebra 1
10-5 Experimental Probability
Impossible
As likely as not
Unlikely
0%
Events with a
probability of
0% never
happen.
Holt Algebra 1
Certain
Likely
50%
Events with a
probability of 50%
have the same
chance of
happening as not.
100%
Events with a
probability of
100% always
happen.
10-5 Experimental Probability
You can estimate the probability of an event by
performing an experiment.
The experimental probability of an event is
the ratio of the number of times the event
occurs to the number of trials. The more trials
performed, the more accurate the estimate will
be.
Holt Algebra 1
10-5 Experimental Probability
Holt Algebra 1
10-5 Experimental Probability
Example 2A: Finding Experimental Probability
An experiment consists of
spinning a spinner. Use the
results in the table to find
the experimental
probability of the event.
Spinner lands on orange
Holt Algebra 1
Outcome
Frequency
Green
15
Orange
10
Purple
8
Pink
7
10-5 Experimental Probability
Example 2B: Finding Experimental Probability
An experiment consists of
spinning a spinner. Use the
results in the table to find
the experimental
probability of the event.
Outcome
Green
15
Orange
10
Purple
8
Pink
7
Spinner does not land on green
Holt Algebra 1
Frequency
10-5 Experimental Probability
Example 3A: Try It Now
An experiment consists of
spinning a spinner. Use the
results in the table to find
the experimental
probability of each event.
Spinner lands on red
Holt Algebra 1
Outcome
Frequency
Red
7
Blue
8
Green
5
10-5 Experimental Probability
Example 3B: Try It Now
An experiment consists of
spinning a spinner. Use the
results in the table to find
the experimental
probability of each event.
Outcome
Red
7
Blue
8
Green
5
Spinner does not land on red
Holt Algebra 1
Frequency
10-5 Experimental Probability
You can use experimental probability to make
predictions.
A prediction is an estimate or guess about
something that has not yet happened.
Holt Algebra 1
10-5 Experimental Probability
Example 4A: Quality Control Application
A manufacturer inspects 500 strollers and finds
that 498 have no defects.
What is the experimental probability that a
stroller chosen at random has no defects?
Find the experimental probability that a stroller has
no defects.
= 99.6%
The experimental probability that a stroller has no
defects is 99.6%.
Holt Algebra 1
10-5 Experimental Probability
Example 4B: Manufacturing Application
A manufacturer inspects 500 strollers and finds
that 498 have no defects.
The manufacturer shipped 3500 strollers to a
distribution center. Predict the number of
strollers that are likely to have no defects.
Find 99.6% of 3500.
0.996(3500) = 3486
The prediction is that 3486 strollers will have no
defects.
Holt Algebra 1
10-5 Experimental Probability
Example 5A: Try It Now
A manufacturer inspects 1500 electric
toothbrush motors and finds 1497 have no
defects.
What is the experimental probability that a
motor chosen at random will have no defects?
Find the experimental probability that a motor has
no defects.
= 99.8%
Holt Algebra 1
10-5 Experimental Probability
Example 5B: Try It Now
A manufacturer inspects 1500 electric
toothbrush motors and finds 1497 have no
defects.
There are 35,000 motors in a warehouse.
Predict the number of motors that are likely to
have no defects.
Find 99.8% of 35,000.
0.998(35000) = 34930
The prediction is that 34,930 motors will have no
defects.
Holt Algebra 1
10-5 Experimental Probability
Points to Remember
# of times the event occurs
• Experimental probability =
# of trials
• Probability can be expressed as a fraction, decimal,
or percent.
Holt Algebra 1
10-5 Experimental Probability
Lesson Quiz: Part I
1. Identify the sample space and the outcome
shown for selecting a marble.
Sample space: {red, green, yellow}
Outcome shown: red
Holt Algebra 1
10-5 Experimental Probability
Lesson Quiz: Part II
2. An experiment consists of spinning a spinner.
Use the results in the table to find the
experimental probability of landing on blue.
Outcome
Frequency
Red
9
Blue
6
Yellow
5
Holt Algebra 1
10-5 Experimental Probability
Lesson Quiz: Part III
3. The neighbors’ dog barked at Tana the last 4
out of 5 times she walked by their house.
a. What is the experimental probability that
the dog barks at Tana when she walks past
the house? 80%
b. Predict the number of times the dog will bark
at Tana if she walks past the house 45 times.
36
Holt Algebra 1