Stats Week 3
The probability of an event and the probability of its complement always sum to:
1
The possible number of combinations of 3-digit elements out of 8 distinct items equals:
56
An experiment consists of three stages. There are three ways to accomplish the first stage, four ways to accomplish the second stage, and five to accomplish the third stage. Then, the number of ways to accomplish the experiment is:
60
An experiment consists of tossing 3 unbiased coins simultaneously. The number of simple events in this experiment is:
8
A false positive in screening (e.g., home pregnancy tests) represents the event that:
A false positive in screening tests is the event that the test is negative for a given condition, given that the person has the condition.
A graphical method of displaying the sample space for an experiment, where each successive level of branching on the tree corresponds to a step required to generate the final outcome, is:
A tree diagram
An experiment is the process by which an observation or measurement is obtained., An event that cannot be decomposed is called a simple event., An event is the collection of one or more simple events.
All of these statements are true.
An event is:
a collection of one or more simple events
The sample space for an experiment can be represented by:
a tree diagram
Any subset of the sample space is called:
an event
Screening tests (e.g., AIDS testing) are evaluated on the probability of a false negative or a false positive, and both of these are:
marginal probabilities
All the outcomes (simple events) contained in one or the other of two random events, or possibly in both, make up:
the union of two events
If events A and B are mutually exclusive, then the probability of both events occurring simultaneously is equal to:
0
Two events A and B are said to be dependent if and only if:
Event A is affected or changed by the occurrence of event B, or vice versa
A false positive in screening tests is the event that the test is negative for a given condition, given that the person has the condition.
False
There is no difference between simple events and events.
False
If P(A/B) = P(A), or P(B/A) = P(B), then events A and B are said to be:
Independent
Which of the following best describes the concept of conditional probability?
It is a measure of the likelihood that a particular event will occur, given the fact that another event has already occurred or is certain to occur.
The set of all simple events of an experiment is called:
Sample Space
Which of the following statements is correct?
The experiment of rolling a single die once contains 6 simple events.
Which of the following statements is false?
The probability of getting the king of spades when randomly drawing a card from a well-shuffled deck is 4/52.
A tree diagram shows only mutually exclusive events.
The statement is false
Which of the following correctly describes experiments
They are activities that result in one and only one of several clearly defined possible outcomes and that do not allow us to tell in advance which of these will prevail in any particular instance.
f A and B are independent events with P(A) = 0.30 and P(B) = 0.50, then P(A/B) is 0.15.
This statement false
All the outcomes contained in one or the other of two events (or possibly in both) constitute the intersection of two events.
This statement is false
Combinations are distinguishable ordered arrangements of items all of which have been drawn from a given group of items.
This statement is false
Conditional probability is the probability that an event will occur, with no other events taken into consideration.
This statement is false
If A and B are independent events with P(A) = 0.30 and P(B) = 0.50, then P(A/B) is 0.15.
This statement is false
If P(A) = 0.60, P(B) = 0.40, and P(B / A) = 0.60, then P(A / B) = 0.24.
This statement is false
Invariably, Venn diagrams illustrate only the intersection of two events.
This statement is false
Simple events of an experiment that take on values between 0 and 1 are inclusive.
This statement is false
The intersection of events A and B is the event that A or B or both occur.
This statement is false
Two events A and B are said to be independent if and only if P(A / B) = P(B) or P(B / A) = P(A).
This statement is false
An experiment consists of tossing 4 unbiased coins simultaneously. The number of simple events in this experiment is 16.
This statement is true
An experiment is any activity that results in one and only one of several clearly defined possible outcomes but that does not allow us to tell in advance which of these will prevail in any particular instance.
This statement is true
Bayes' Rule is a formula for revising an initial subjective (prior) probability value on the basis of results obtained by an empirical investigation and for, thus, obtaining a new (posterior) probability value.
This statement is true
Different events that have no outcomes in common are mutually exclusive events
This statement is true
If P(A / B) = P(A), then events A and B are said to be independent.
This statement is true
If P(A) > 0 and P(B) > 0, then when A and B are mutually exclusive events, they are also dependent events.
This statement is true
The probability of an event A is equal to the sum of the probabilities of the simple events contained in A.
This statement is true
When a patient who is complaining of several specific symptoms arrives at a doctor's office, the doctor who makes the diagnosis says that she is 90% certain that the patient has the flu, it is likely that she is basing her assessment on relative frequency approach of assigning probabilities.
This statement is true
When the population is unknown and only a sample from that population is available, probability is used for statistical inference to draw reliable conclusions from sample information about the population.
This statement is true
Probability is the tool that allows the statistician to use sample information to make inferences about or describe the population from which the sample was drawn.
This statement. is true
An event is a collection of one or more simple events of an experiment.
True
If an investor was interested in assessing the probability that a new supermarket will be successful in a New York market area, he would most likely use the relative frequency definition of probability as the method for assessing the probability of success.
True
