This is a basic PowerPoint presentation on probability. Complex term are made simple using clear examples.

1. PROBABILITY!!
Notes
Examples
Sample Problems

2. Definition
Probability is the measure of how
likely something will occur.
It is the ratio of desired outcomes to
total outcomes.
(# desired) / (# total)
Probabilities of all outcomes sums to
1.

3. Example
If I roll a number cube, there are six
total possibilities. (1,2,3,4,5,6)
Each possibility only has one outcome,
so each has a PROBABILITY of 1/6.
For instance, the probability I roll a 2
is 1/6, since there is only a single 2 on
the number cube.

4. Practice
If I flip a coin, what is the
probability I get heads?
What is the probability I get tails?
Remember, to think of how many
possibilities there are.

5. Answer
P(heads) = 1/2
P(tails) = 1/2
If you add these two up, you will get
1, which means the answers are
probably right.

6. Two or more events
If there are two or more events, you
need to consider if it is happening at
the same time or one after the other.

7. “And”
If the two events are happening at
the same time, you need to multiply
the two probabilities together.
Usually, the questions use the word
“and” when describing the outcomes.

8. “Or”
If the two events are happening one
after the other, you need to add the
two probabilities.
Usually, the questions use the word
“or” when describing the outcomes.

9. Practice
If I roll a number cube and flip a
coin:
What is the probability I will get a
heads and a 6?
What is the probability I will get a
tails or a 3?

10. Answers
P(heads and 6) = 1/2 x 1/6 =1/12
P(tails or a 5) = 1/2 + 1/6 = 8/12 = 2/3

11. Experimental Probability
An experimental probability is one
that happens as the result of an
experiment.
(# of outcomes) / (# of trials)
The probabilities we have done so far
are “theoretical probabilities”,
because there was no experiment.

12. Experiment
Flip a coin 50 times, and write down
what happens for each flip.
In the end, find the experimental
probabilities by writing the how many
times heads and tails occurred over
the total number of trials (flips)