Transcript 10.3-probability

Definitions
Probability is the mathematics of chance.
It tells us the relative frequency with which we can
expect an event to occur
The greater the probability the more
likely the event will occur.
It can be written as a fraction, decimal, percent,
or ratio.
Definitions
1
Certain
.5
50/50
Probability is the numerical
measure of the likelihood that
the event will occur.
Value is between 0 and 1.
Sum of the probabilities of all events
is 1.
0
Impossible
Definitions
There are three types of probability
1. Theoretical Probability
Theoretical probability is used when each outcome
in a sample space is equally likely to occur.
P(E) =
Number of Event Outcomes
Total Number of Possible Outcomes in S
The Ultimate probability formula 
Definitions
There are three types of probability
2. Experimental Probability
Experimental probability is based upon observations
obtained from probability experiments.
P(E) =
Number of Event Occurrences
Total Number of Observations
The experimental probability of an event
E is the relative frequency of event E
Definitions
There are three types of probability
3. Subjective Probability
Subjective probability is a probability measure
resulting from intuition, educated guesses, and
estimates.
Therefore, there is no formula to calculate it.
Usually found by consulting an expert.
• Tickets numbered 1 to 20 are mixed up
and then a ticket is drawn at random.
What is the probability that the ticket
drawn has a number which is a multiple of
3 or 5?
• A bag contains 2 red, 3 green and 4 blue
balls. Two balls are drawn at random.
What is the probability that none of the
balls drawn is blue?
• In a box, there are 8 red, 7 blue and 6
green balls. One ball is picked up
randomly. What is the probability that it is
neither red nor green?
•
• The diagram shows a spinner made up of a
piece of card in the shape of a regular pentagon,
with a toothpick pushed through its center. The
five triangles are numbered from 1 to 5.
The spinner is spun until it lands on one of the
five edges of the pentagon. What is the
probability that the number it lands on is odd?
• Each of the letters of the word
MISSISSIPPI are written on separate
pieces of paper that are then folded, put in
a hat, and mixed thoroughly.
One piece of paper is chosen (without
looking) from the hat. What is the
probability it is an I?
• A card is chosen at random from a deck of
52 playing cards.
There are 4 Queens and 4 Kings in a deck
of playing cards.
What is the probability it is a Queen or a
King?
• If there are six horses in a race and each
horse has an equal chance of winning,
what is the probability of you picking the
top three finishers in perfect order?
• A fair coin is tossed three times. What is
the probability of obtaining one Head and
two Tails?
(A fair coin is one that is not loaded, so
there is an equal chance of it landing
Heads up or Tails up.)