1. Likelihood, Theoretical, and Experimental
Probability
Likelihood, Theoretical, and Experimental

2. Outcome Event Probability As likely as not Impossible
Use these words to fill in the blanks on your worksheet from Ready p. 280
Outcome
Event
Probability
As likely as not
Impossible
Less likely than likely
Certain
More likely than not

3. THINK… Unlikely Likely Impossible Certain Equally likely
Label the shaded circles with the following phrases…
Unlikely
Likely
Impossible
Certain
Equally likely

4. REFLECT…What did you say?
Impossible:
Certain:
As likely as not:
More likely than not:
A name that starts with “H”
A name that starts with “J”
A girl’s name
A name that has double letters

5. Looking at different events and their outcomes will help you understand probability concepts…
A bag has 24 marbles: 6 green, 6 red, and 12 blue. Lucy reaches in the bag and picks out one marble. 24
1. What is the total number of marbles?
2. What is half of the total number of marbles? 12
3. Name an outcome that is impossible.
Picking purple
4. Name an outcome that is certain.
Picking a marble
5. Name an outcome that is as likely as not.
Picking blue
6. Name an outcome that is more likely than not.
Picking blue OR red
7. Name an outcome that is less likely than not.
Picking red

6. Now you try… Name an outcome that has a probability of… 1 ½1
Between 0 and ½
Between ½ and 1
Picking a D
Picking an A, B, or C
Picking an A
Picking a C
Picking an A or a B

7. UNIFORM vs. NON-UNIFORM!
Compare the spinners and the probability of spinning a red in words and chances of occurrance.
UNIFORM vs NON-UNIFORM!

8. EXPERIMENTAL PROBABILITY
What do you think it is?
When you find the probability of an event based on the results from an experiment.
Number of outcomes
Number of trials

9. THEORETICAL PROBABILITY
What do you think it is?
What you would EXPECT to happen in an experiment.
Number of FAVORABLE outcomes
Total number of outcomes
Sample space: the set of possible outcomes, for example, flipping a coin would have a sample space of “heads” or “tails”.

10. NOTATION P(3) is read “the probability of rolling a 3”
P(blue) is read “the probability of picking a blue”
P(King or a Queen) is read “the probability of picking a king or a queen”

11. THINK ABOUT THESE QUESTIONS…
1. If you roll a number cube and get an even number, will that impact your next outcome? Why or why not?
2. How can you get EXPERIMENTAL probability to get closer to the THEORETICAL probability ?

12. Let’s try it!!