# Probability by opza81

VIEWS: 0 PAGES: 19

• pg 1
```									       Probability

By: Alex von Ebers and Lyndsi
Monjon
Probability Defined
• Probability is the relative possibility that an
event will occur, as expressed by the ratio
of the number of actual occurrences to the
total number of possible outcomes
(dictionary.com).
• Our Definition
– the chance that one specific outcome will
happen out of multiple options.
Theoretical Probability
• Theoretical probability is when you can get
the probability but you can’t be absolutely
sure that the subject is fair to both sides.
• For example, the probability of a coin
landing on heads is fifty percent. This is
only true if the coin is fair, and we are able
to assume that the coin has an equal
chance to land on heads or tails.
Empirical Probability
• Empirical probability is when you find a
probability based on experiments and
observations (Bennett 432).
• An example of this is if you had five
earthquakes in the last forty years. The
probability that you could have an
earthquake the next year is .125 or about
one earthquake in every eight years.
Subjective Probability
• Subjective probabilities are when you make an
estimate based on past experiences or intuition
(Bennett 435).
• An example of that would be if someone was to
say that they are seventy-five percent sure that
you are going to get in a car crash in the next
year. This is a subjective probability because
they are basing this on their experiences with
you and their intuition.
History
• Many of the mathematicians who first
developed the theory of probability were
gamblers (Vorderman 79).
• A gambler’s dispute in 1654 led to the
creation of a mathematical theory of
probability (Apostol).
History Continued
• No general theory was developed before a
famous correspondence between two
French men, Blaise Pascal and Pierre de
Fermat (Apostol).
• In 1657, Dutch scientist, Christian
Huygens wrote the first book on probability
(Apostol).
More History
• It was not until the twentieth century that a
definition was decided on because it was
hard to find something good enough for
mathematics, yet comprehensive enough
to be applicable to a wide range of
phenomena (Apostol).
How to Find Theoretical Probability
1) Count the total number of possible
outcomes
2) Among all the possible outcomes, count
the number of ways the event of interest,
A, can occur.
3) Determine the probability , P(A), from the
following equation
P(A)= number of ways A can occur
total number of outcomes
How to Find Empirical Probability
1) Find the number of observed events.

2) Divide that by the amount of time or total
number of events.
How to Find Subjective Probability
• No formal equation for subjective
probability.
• Based off of experience and/or intuition.

• Knowing the three types of Probability,
which one would you use to figure out the
probability of picking a certain color of
skittle?
Probability and Everyday Life
•   Gambling/Games of Chance
•   Medical Checks
•   Sports
•   Pregnancy
– Date of Birth
– Gender
– Genetics
Activities
• Flipping a coin

• Rolling Dice

• Chance of Rain

• Rock, Paper, Scissors
Skittles
• We are going to find the probability of
reaching into a bag and pulling out a
specific color skittle.
• We will figure the probability of grabbing
each color.
Activity
•   Count each color of skittle
•   Record on sheet
•   Add up each number to find the total
•   Write down the percentage of getting each
color.
Small Bag
•   Red: 14 skittles, 23.3%
•   Orange: 12 skittles, 20%
•   Yellow: 15 skittles, 25%
•   Green: 9 skittles, 15%
•   Purple: 10 skittles, 16.7%
•   Total: 60 skittles
Big Bag
•   Red: 102 skittles, 24.4%
•   Orange: 61 skittles, 14.6%
•   Yellow: 129 skittles, 30.9%
•   Green: 66 skittles, 15.8%
•   Purple: 60 skittles, 14.4%
•   Total: 418 skittles
• Total number of skittles per bag
• Each Color
Works Cited
•   Apostol, Tom M. A Short History of Probability. 1969. 20 Nov. 2006
<http://www.cc.gatech.edu/classes/cs6751_97_winter/Topics/stat-
meas/probHist.html>.
•   Bennett, Jeffrey, and William Briggs. Using and Understanding
Mathematics: a Quantitative Reasoning Approach. 3rd ed. Boston: Greg
Tobin, 2005. 430-451.
•   Littlefield, Cindy A. Real-World Math for Hands-on Fun! Charlotte:
Williamson, 2001. 90-100.
•   Packel, Edward. The Mathematical Game of Gambling. Washington: The
Mathematical Association of America, 1981. 20-62.
•   "Probability." Dictionary.Com. 28 Nov. 2006
•   The Probability in Everyday Life. 27 Nov. 2006
<http://media.wiley.com/product_data/excerpt/13/04717514/0471751413.pd
f>.
•   Vorderman, Carol. How Math Works. Pleasantville: Reader_Digest, 1996.
69-81.

```
To top