1. 2. Find the probability of drawing a vowel.
Do Now
Find the probabilities. Write your answer as a fraction, as a decimal to the nearest hundredth, and as a percent to the nearest whole percent.
You have 11 cards, each with one of the letters from the word mathematics.
1. Find the probability of drawing an m from the pile of shuffled cards.
2. Find the probability of drawing a vowel.
3. Find the probability of drawing a consonant. 2 11
, 0.18, 18% 4 11
, 0.36, 36% 7 11
, 0.64, 64%

2. Learn to find experimental probability.

3. Experimental probability is one way of estimating the probability of an event.
The experimental probability of the event is found by comparing the number of times an event occurs to the total number of trials.

4. The more trials you have, the more accurate the estimate is likely to be.

6. number of times an event occurs total number of trials
Example A:
During skating practice, Sasha landed 7 out of 12 jumps. What is the experimental probability that she will land her next jump?
P(event) 
number of times an event occurs
total number of trials
number of jumps landed
number of jumps attempted
P(jumps landed)  7 12 =
The experimental probability that Sasha will land her
next jump is or approximately 0.58 or 58%. 7 12

7. number of times an event occurs total number of trials
YOU TRY 1
During basketball practice, Martha made 9 out of 10 free throws. What is the experimental probability that she will make her next attempt?
P(event) 
number of times an event occurs
total number of trials
P(free throws made) 
number of free throws made
number of free throws attempted 9 10
= = 90%
Substitute data from the experiment and write as a percent.
The experimental probability that Martha will make the
next free throw is or 90% or 0.9. 9 10

8. YOU TRY 2
Students have checked out 55 books from the library. Of these, 32 books are fiction.
What is the experimental probability that the next book checked out will be fiction?
number of fiction books checked out
total number of books checked out
P(fiction)  32 55 
Substitute data.
The experimental probability that the next book checked out will be fiction is approximately 32 55 .

9. YOU TRY 2 continued
What is the experimental probability that
the next book checked out will be nonfiction?
P(nonfiction) = 23 55
The experimental probability that the next book checked
out will be nonfiction is approximately 23 55 .

10. number of pears selected
Extra Example
Students have a fruit choice for lunch of an apple or a pear. So far 18 of 47 students have selected pears.
What is the experimental probability that the next fruit selected will be a pear?
P(pear) 
number of pears selected
total number of fruit selected 18 47 
Substitute data.
The experimental probability that the next fruit selected will be a pear is approximately 18 47 .

11. Extra Example
What is the experimental probability that
next fruit selected will be an apple?
P(apple) = 29 47
Simplify.
The experimental probability that the next fruit selected will be an apple is 29 47 .

12. Lesson Quiz
1. In a soccer shoot-out, Bryan made 4 out of 9 goals. What is the experimental probability that he will make the next shot?
2. It has rained on the last 2 out of 10 Fourth of July parades in Swanton.
A. What is the experimental probability that it will rain on the Fourth of July parade this year?
B. What is the experimental probability that it will not rain on the Fourth of July parade this year? 4 9 1 5 4 5

13. Lesson Quiz for Student Response Systems
1. During a shot put practice session, Greg crossed the 70-foot mark in 15 out of 21 attempts. What is the experimental probability that he will cross the 70-foot mark in his next attempt? A. B. C. D. 2 7 5 7 6 7 7 5 13 13 13

14. Lesson Quiz for Student Response Systems
2. Simon is practicing basketball. He made 33 of 42 free throws he attempted. What is the experimental probability that we will make his next free throw? A. B. C. D. 9 14 11 42 11 14 14 11 14 14 14

15. Lesson Quiz for Student Response Systems
3. Rachel found that 20 out of 48 cars that entered a parking lot were red. What is the experimental probability that the next car that comes in is red? What is the experimental probability that the next car that comes in is not red? A. B. C. D. 15 15 15