1. 1. What’s the probability that the spinner will land on blue?
Bell Work
1. What’s the probability that the spinner will land on blue?
2. Samuel has a bowl of fruit containing 3 apples, 2 oranges and 5 pears. If he randomly picks 1 piece of fruit from the bowl, what is the probability it will be a pear or an apple?

2. Answers + 1. 2. 1 2 3 4 5 6 7 8 apples 3 2 oranges 5 pears
10 fruits total 2.

3. Experimental Probability

4. Theoretical vs. Experimental Probability
Theoretical Probability:
- It is how a probability of an event “should” happen.
Experimental Probability:
- Experimental probability refers to the probability of an event occurring when an experiment was conducted.

5. Theoretical Probability
Hint: Your three options are green, blue and red. Their probability will add up to 100%
Answer: 63%

6. Experimental probability
P(event) = number of times event occurs
total number of trials
You tossed a coin 10 times and recorded heads 3 times and tails 7 times
P(head)= 3/10 , 0.3 or 30%
A head shows up 3 times out of 10 trials,
P(tail) = 7/10, 0.7 or 70%
A tail shows up 7 times out of 10 trials
HEADS
TAILS

7. Comparing experimental and theoretical probability
Both probabilities are ratios that compare the number of favorable outcomes to the total number of possible outcomes
All results will add up to 100% every time!
P(head)= 3/10 or 30%
P(tail) = 7/10 or 70%
P(head) = 1/2 or 50%
P(tail) = 1/2 or 50%

8. Experimental Probability
You draw a marble out of the bag, record the color, and replace the marble. After 5 draws, you record 2 red marbles. According to your experiment what is the probability of drawing each color?
P(red)= 2/5, 0.4 or 40%
P(blue)= 3/5, 0.6 or 60%

9. Number of favorable outcomes Total number of rolls = 0.18 = 18%
EXAMPLE 2
You roll a number cube 100 times. Your results are given in the table below. Find the experimental probability of rolling a 6. Write your answer as a percent.
P(rolling a 6) = 18
100
Number of favorable outcomes
Total number of rolls
= 0.18 = 18%
If you rolled the number cube 300 times then how many times would you predict that you would roll a 3?
60 times

10. Rolled # of times 1 6 2 15 3 18 4 11 5 7 Experimental:
P(rolling a 4) = 3/60 = 1/20
Theoretical:
P(rolling a 4) = 1/6

11. Experimental Probability
Example
A class group flipped a coin and recorded their results below. What is their experimental probability of landing on heads?
Solution
The group landed on heads 6 times, so the experimental probability is:
Trial: 1 2 3 4 5 6 7 8 9 10
Result: T H

12. A,B,C,D,E
1/5 = 20%

13. Practice: Experimental Probability Worksheet