Download Example 1: A fair die is thrown

Name: _______________________ Date: __________
Intro to Probability!
Example 1: A fair die is thrown. What is the
probability of obtaining:
a) a five?
b) an even number?
Example 2: A bag contains 4 black balls and 6
white balls. A ball is chosen from the bag at
random. What is the probability of choosing a
white ball?
Example 3: Our class contains ___ people:
___ with blue eyes, ___ with green eyes, ___
with brown eyes, and ___ with other colors.
The probability of selecting a person at random
with brown eyes is:
Example 4: When a batch of 145 paper clips
were dropped onto 6 cm by 6 cm squared
paper it was observed that 113 fell completely
inside squares and 32 finished up on the grid
lines. Find, to 2 decimal places, the estimated
probability of a clip falling
a) inside a square ______ b) on a line______
Terms to Know!
1. The number of ______________ is the total number of times the experiment is repeated.
2. The _________________ are the different results possible for one trial of the experiment.
3. The _________________ of a particular outcome is the number of times that this outcome is
observed.
4. The list of all possible outcomes is called the _________________________.
5. The outcome, or set of outcomes, in whose probability we are interested is called a(n)
______________.
6. A selection is _______________ if each item to be selected is equally likely to be chosen.
7. The _____________________________ of an outcome is the frequency of that outcome
expressed as a fraction or percentage of the total number of trials.
Example Sample Space (list all possible
outcomes)
1
Event
Probability
2
3
4
*Can you develop a formula for finding the probability of an event A? ________________________
HW p. 372-373 #1-3, 15
In the diagram below, ____ represents __________ _____________, and the oval represents the
__________ ___.
n(A) = _____________________________________
n(U) = _____________________________________
P(A) = _____________________________________
P(A) =
Sooooo… The probability of A = _____________________________________________
Ways to Find Sample Space: Before, we only talked about rolling one die, but what if you
roll two, three? It’s best to make an organized list or a table.
Example 5: Two fair dice are thrown. Find the probability that the total of the scores on the two
dice is six. First, list the possible outcomes (i.e. the ________________________). How many will
there be? _______ . There are two possible ways to do this:
1. List the possible outcomes.
2. Table
___________________
1
2
3
4
5
6
1
2
3
4
5
6
Let A be the event that the total score is six.
What are the possible ways to get a total score of six? ____________________________
n(A) = ________ and n(U) = _________ so P(A) = _____
Example 6: Illustrate the possible outcomes when 2 coins are tossed.
1. 2-D Grid
2. Tree Diagram
You do:
1. Again two fair dice are thrown. What is the probability of getting a total score of 11?
2. The table shows the number of seeds in a seed pod of a sample of 100 plants of a specific
species.
Seeds per pod
 10 11
12
13
14
15
16
17
 18
Number of pods
2
21
24
19
11
8
4
3
8
Find the probability that a seed pod selected at random from the samples contains:
(a) 14 seeds
(b) more than 14 seeds