The Wonderful World…
of Probability
When do we use
Probability?
Flip a coin and roll a dice
How many possibilities can occur?
Flip 3 coins and roll a dice
Flip 5 coin and roll 2 dice
Some Key Definitions
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Outcome: A possible result of an
experiment
Event: When a predicted outcome
comes to pass
Sample Space: All possible outcomes
The coin flipping experiment
Everybody in the classroom must flip a coin.
What would you expect the number of
heads and tails to be?
Is your prior guess consistent with the
actual experiment?
Theoretical Probability
What one would expect the event to look
like, on average
Number of favorable outcomes
Theoretical Pr obability 
Number of attempts
Experimental Probability
What the actual probability is after an
experiment is conducted
Number of successes
Experiment al Pr obability 
Number of trials
The chances of picking a
face card in a deck
Theoretical Probability:
Experimental Probability:
What are the odds?
Number of favorable outcomes
Odds in favor 
Number of unfavorabl e outcomes
Number of unfavorable outcomes
Odds against 
Number of favorable outcomes
Factorials
The product of the integers from 1 to
that number
5!
The Phillies can have 9 players play
at one time. How many possible
batting orders can the manager
create?