1. Unit 8 Probability Quiz Review
Ch. 9
Lessons 1, 2, 5, 6 and 7

2. 9-1 Probability of Simple Events
P(event) = 𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑓𝑎𝑣𝑜𝑟𝑎𝑏𝑙𝑒 𝑜𝑢𝑡𝑐𝑜𝑚𝑒𝑠 𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑝𝑜𝑠𝑠𝑖𝑏𝑙𝑒 𝑜𝑢𝑡𝑐𝑜𝑚𝑒𝑠
Probability is a number between 0 and 1
Near 0 =very unlikely
Near 1 = very likely

3. 9-1 Probability can be written as fraction, decimal, or percent
Simplify all fractions
Fraction to decimal
Divide numerator by denominator
Decimal to percent
Multiply decimal by 100 (move decimal two places to right)

4. 9-1
Eight cards are marked 3, 4, 5, 6, 7, 8, 9, and 10 such that each card has exactly one of these numbers. A card is picked without looking. Find each probability. Write each answer as a fraction, a decimal, and a percent.
1.) P(9) ) P(3 or 4)
3.) P(greater than 5) 4.) P(not 6)   

5. 9-1 Complementary Events
Two events in which either one or the other must happen, but they cannot happen at the same time
The sum of the probability of an event and its complement is 1 or 100%
Ex: A coin can either land on tails or not land on tails

6. 9-1
At the Baltimore International Airport, 82% of the flights arrive on time. Suppose a flight that arrived at the airport is selected at random.
What is the probability that the flight did not arrive on time? Write the answer as a fraction, percent, and decimal. Explain your reasoning.
Write a sentence that explains how likely it is for a flight at the Baltimore airport to arrive on time.

7. 9-2 Theoretical and Experimental Probability
Theoretical: what should happen (what’s expected)
Experimental: what actually happens in a probability experiment
Compare the two probabilities by changing the fractions to decimals and writing a sentence
They are close because one fraction is close to the other OR
They are not close because there were not enough trials

8. 9-2
A spinner that is divided into four equal sections is spun 100 times and it lands on green 32 times.
Find the experimental probability of landing on green.
Find the theoretical probability of landing on green.
Compare the experimental probability to the theoretical probability.

9. 9-2 Predict Future Events
Find the probability from the original problem
Simplify it
Set up a proportion with new total at the bottom of the second fraction and solve for the missing part

10. 9-2
Use the graph of a survey of 24 seventh-grade students asked to name their favorite hobby.
What is the experimental
probability that a student’s
favorite hobby is roller skating
or singing?
Suppose 150 seventh-grade
students were surveyed. How
many can be expected to say
that roller skating or singing is
their favorite hobby?

11. 9-5 Fundamental Counting Principle
Using multiplication instead of a tree diagram to find the number of possible outcomes in a sample space
If there are more than 2 events, continue to multiply event outcomes together to determine the total number of outcomes
Show and label outcomes for each event!
If finding the probability of an event, use FCP to find the total number of outcomes (denominator)
Usually one favorable outcome (numerator)

12. 9-5
Use the Fundamental Counting Principle to find the total number of outcomes for each situation
Selecting one sweatshirt from a choice of five sweatshirts and one pair of pants from a choice of four pairs of pants
Tossing a dime, a quarter, a penny, and rolling a number cube

13. probability it will be a 4-bedroom home with a
The table shows the kinds of homes offered by a residential builder. If the builder offers a discount on one home at random, find the
probability it will be a
4-bedroom home with a
contemporary kitchen and
an open porch. Is it likely or
unlikely for this to occur?
Number of
Bedrooms
Style of
Kitchen
Type of
Porch
5-bedroom
Mediterranean
Open
4-bedroom
Contemporary
Screen
3-bedroom
Southwestern

14. 9-6
Permutations
An arrangement, or listing, of objects in which order is important
Use the Fundamental Counting Principle to find the number of permutations
Once something is chosen, it cannot be chosen again
Use blanks for number of objects!
If finding the probability of an event, find the permutation (total number of outcomes) first
Usually one favorable outcome (numerator)

15. 9-6
Use the Fundamental Counting Principle to find the total number of outcomes for each situation
There are 4 passengers in a car. In how many ways can the passengers sit in the 4 passenger seats of the car?
Mr. Bernstein owns 14 paintings, but has only enough wall space in his home to display three of them at any one time. How many ways can Mr. Bernstein display three paintings in his home?

16. 9-6
Glen received 6 birthday cards. If he is equally likely to read the cards in any order, what is the probability he reads the card from his parents first and the card from his sister second?

17. 9-7 Independent and Dependent Events
Independent: when one event does not affect the outcome of the other event
Ex: spinning a spinner and rolling a number cube
Find the probability of each event as fraction and multiply them
Simplify answer

18. 9-7
Dependent: the outcome of the first event affects the outcome of the second event
Ex: You have a bag of marbles. You pick one marble, DO NOT REPLACE IT, and pick another one
Number of outcomes usually changes for the second event
Find the probability of the first event FIRST, then the second event and multiply them
Simplify answer

19. 9-7
The two spinners at the right are spun. Find each probability. (Independent or Dependent?)
P(less than 5 and B)
P(odd and A)

20. 9-7
There are three quarters, five dimes, and twelve pennies in a bag. Once a coin is drawn from the bag, it is not replaced. If two coins are drawn at random, find each probability. (Independent or Dependent?)
P(a quarter and then a penny)
P(two dimes)