Experimental
vs. Theoretical
Probability
Probability is…

A measure of how likely an event is to occur
Theoretical vs. Experimental Probability
Theoretical Probability:
- The probability we find on paper.
- It is the probability of an event based on
what “should” happen.
Experimental Probability:
- Experimental probability refers to the
probability of an event occurring based
on the results of an experiment.
Theoretical vs. Experimental Probability
Theoretical Probability:
Theoretical Probability =
number of favorable outcomes
number of possible outcomes
Theoretical vs. Experimental Probability
Experimental Probability:
Experimental Probability =
number of event occurrences
Total number of trials
Theoretical vs. Experimental Probability
Example 1: Roll a dice.
What is the theoretical probability of rolling
a 4?
# favorable outcomes
# possible outcomes
1
6
The probability of rolling a 4 is 1 out of 6
Theoretical vs. Experimental Probability
Example 1 Continued: Roll a die.
What is the experimental probability of
rolling a 4?
# event occurrences
Total # of trials
Theoretical vs. Experimental Probability
Example 2: Counters.
What is the theoretical probability of
flipping a yellow?
# favorable outcomes
# possible outcomes
1
2
The probability of flipping a yellow is 1 out of 2 or .5 or
50%
Theoretical vs. Experimental Probability
Example 2 Continued: Counters.
What is the experimental probability of
flipping a yellow?
# favorable outcomes
# possible outcomes
Theoretical vs. Experimental Probability
Summary:
- Theoretical Probability is how often an
outcome “should” happen, in theory.
- Experimental probability refers to the
probability of an event occurring based
on an experiment.
Theoretical vs. Experimental Probability
Clear your desks for a short quiz.