chapter 4
Based on past data, the probability that a new hire at Company XYZ will be successful is 0.70. The company has started using an applicant screening test. Given the applicant scores well on the test, the probability the new hire will be successful is 0.70. The events 'new hire being successful' and 'applicant scoring well' are
independent.
intersection
s a particular outcome of an experiment.
A(n) ______ of an experiment contains all possible outcomes of the experiment.
sample space
subjective probability.
hese probabilities are based on personal judgment.
A probability based on logical analysis rather than on observation or personal judgment is BEST referred to as a
classical probability.
probability is the probability of an event given that another event has already occurred.
conditional
And
'And' is associated with the intersection.
measures the likelihood of a subset occurring.
probability
How would you express the probability that a customer at the movie theater will order a drink (D) given that the customer orders popcorn (P
P(D|P)
The probability of tossing a head on a coin is 0.5.
This is a classical probability
The probability of rolling a '2' on a single die is 1/6.
This is a classical probability.
A skier believes she has a 0.10 chance of winning a gold medal at the next Olympics.
This is a subjective probability.
An event
any subset of outcomes of the experiment.
Which of the following is an example of a conditional probability
The probability that Lisa passes the test, given that she attends class and does the homework.
The probability that a customer will purchase a product is 0.20. The probability that a customer is a male is 0.5. The probability that a customer is a male and will purchase a product is 0.10. The events purchasing a product and being a male areThe probability that a customer will purchase a product is 0.20. The probability that a customer is a male is 0.5. The probability that a customer is a male and will purchase a product is 0.10. The events purchasing a product and being a male are
independent. Rationale: Independent since P(A) × P(B) = 0.15 × 0.5 = 0.075 = P(A ∩ B)
The sum of the probabilities of a list of mutually exclusive and collectively exhaustive events is
one.
A softball coach believes that Laurie has a 0.25 probability of getting a hit against a particular pitcher that Laurie has never batted against before. What method was used to assign this probability
subjective probability.
A subset of the sample space is called a/an
event
If two events are independent, then the probability that both events occur equals
the product of the individual probabilities.
The addition rule is used to calculate
the union of two events.
What assumption is made with classical method of determining probabilities
All outcomes are equally likely.
Which one of the following words is associated with the union of two events?
Or
A statistics student interviews for a job. After being asked what her chances of getting the job are, she states that the thinks she has an 80% chance of getting the job. What type of method did she use to determine this probability
Subjective
Probability values range from
zero to one.
Let event Z be an outcome of an experiment. What are possible probabilities for Z? Select all that apply.
0 0.12 1.00
When rolling a pair of dice and summing the two values rolled, which of the following are exhaustive events? Select all that apply.
A sum of 7 or more and a sum of 6 or less. Rationale: This includes all possible outcomes. An even number and an odd number. Rationale: This includes all possible outcomes. A sum of 6 or more and a sum of 8 or less. Rationale: This includes all possible outcomes
Suppose you have flipped a fair coin 10 times and all 10 flips have come up tails. What does the law of large numbers indicate will happen
After many more flips, the empirical results will approach 50% heads and 50% tails.
example of experiments
Record the number of computers sold next month at a computer store. Rationale: The different outcomes are the numbers 0, 1, 2, ... Ask someone who he or she thinks will win the baseball World Series. Rationale: The possible outcomes are different baseball teams. Select a single card from a deck of cards. Rationale: There are 52 different outcomes (cards.)
When considering the union of two events, A and B, which ones of the following would be included? Select all that apply.
The outcomes that are in both events A and B. The outcomes that form event B. The outcomes that are not in event A and not in event B. Rationale: This would be the complement of the union. The outcomes that form event A
experiment
The subset represents outcome(s) of the experiment, not the experiment.
An classical probability
These are created through logical deduction.
If an experiment is selecting a card from a deck of cards, then the sample space is
all the cards in the deck.
The conditional probability of A given B is calculated by dividing the probability of intersection of A and B by the probability of
b
Using the multiplication rule, the probability that event A and event B both occur is computed by multiplying the conditional probability of event A given event B by the probability of
event B.
Assume the sample space S = {win, lose}. Which numbers define valid probabilities?
P(win) = 0.8, P(lose) = 0.2
Kareem is trying to decide which college to attend full time next year. Kareem believes there is a 55% chance that he will attend State College and a 33% chance that he will attend Northern University. The probability that Kareem will attend either State or Northern is
0.88
For any given event, the probability of that event and the probability of the complement of the event must sum to
1.0
simple event
A simple event contains a single outcome of the experiment.
The relative frequency of an event is used to calculate what type of probability?
An empirical probability
Which of the following is NOT an example of an experiment?
Determine a historical fact such as the name of the U.S. President in the year 1856. Rationale: There is only one possible outcome (president) in the year 1856.
Given
Given' is associated with conditional events.
Not
Not' is associated with a complementary event.
How many outcomes of an experiment constitute a simple event?
One
More than one
Only one outcome comprises a simple event.
For two events A and B, the multiplication rule is
P(A∩B) = P(A|B) × P(B). Rationale: Event B occurs first. Then A happens second given that B has already occurred.
How would you express the probability that a customer at the movie theater will order a drink (D) given that the customer orders popcorn (P)
P(D|P)
Sometimes the union of two events will be overstated if the union is found by adding just the individual probabilities. What is done to keep from overstating the probability of the union of two events?
The intersection of the event is subtracted.
A subjective probability
These are created through personal judgment.
soft ball
classical probability. Rationale: Classical probability would assume that the chances of a hit and no hit are equally likely. empirical probability. Rationale: There is no prior data about this batter hitting against this pitcher. correlated probability. Rationale: This is not a method of assigning probabilities.
Mutually exclusive and exhaustive events
contain all outcomes in an experiment and do not share common outcomes
empirical probability.
hese probabilities are based on observed data.
The fact that an empirical probability will approach the classical probability if an experiment is conducted many times is known as the
law of large numbers.
A numerical value that measures the likelihood of an uncertain event is a
probability
The conditional probability of A given B is calculated by dividing the probability of intersection of A and B by the probability of
B.
Which of the following BEST represents an empirical probability
Based on past data, a manager believes there is a 83% selling out of a particular product today. Rationale: Empirical probabilities are calculated from observed data.
Why does the addition rule for mutually exclusive events not subtract the intersection of the two events
Because their intersection is 0.
