ECON10 Chapter4

The intersection of events A and B is the event that A or B or both occur.

False

The probability that event A will not occur is 1- P(A^c) .

False

There is no difference between simple events and events.

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).

False

If events A and B are mutually exclusive, then the probability of both events occurring simultaneously is equal to:

0

If P(A) = 0.30, P(B) = 0.40 and P(A n B) = 0.20, then P(A / B) is:

0.50

If P(A) = 0.80, P(B) = 0.70 and P(A u B) = 0.90, then P(A n B) is:

0.60

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

Which of the following statements is false?

An event that can be decomposed into two is called a simple event.

If P(A) = 0.42 and P(B) = 0.38, then P(A n B) is:

Cannot be determined from the given information.

A false negative in screening tests is the event that the test is positive for a given condition, given that the person does not have the condition.

False

A tree diagram shows only mutually exclusive events.

False

All the outcomes contained in one or the other of two events (or possibly in both) constitute the intersection of two events.

False

Combinations are distinguishable ordered arrangements of items all of which have been drawn from a given group of items.

False

Conditional probability is the probability that an event will occur, with no other events taken into consideration.

False

If P(A) = 0.4, P(B) = 0.5, and P(A n B) = 0.20, then the events A and B are mutually exclusive.

False

If P(A) = 0.60, P(B) = 0.40, and P(B / A) = 0.60, then P(A / B) = 0.24.

False

Which of the following clearly describes the general multiplicative rule of probability?

It is a rule of probability theory that is used to compute the probability for an intersection of two or more events: for any two events, A and B, P(A n B) = P(A) * P(B/A) = P(A n B) = P(A/B) *P(B)

In the case of independent events A, B, and C, P(A n B n C) equals:

P(A)*P(B)*P(C)

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 diamonds when randomly drawing a card from a well-shuffled deck is 1/52. The probability of getting a black card when randomly drawing a card from a well-shuffled deck is 1/2. The probability of getting a 10 when randomly drawing a card from a well-shuffled deck is 4/52. The probability of getting two heads when tossing a fair coin twice is 1/4. The probability of getting the king of spades when randomly drawing a card from a well-shuffled deck is 4/52.

The probability of getting the king of spades when randomly drawing a card from a well-shuffled deck is 4/52.

An experiment consists of tossing 4 unbiased coins simultaneously. The number of simple events in this experiment is 16.

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.

True

The complement of an event A, denoted by A^c, consists of all the simple events in the sample space S that are not in A.

True

Two events A and B are said to mutually exclusive if P(A n B) = 0.

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.

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.)

True

An event is:

a collection of one or more simple events

The set of all simple events of an experiment is called:

a sample space

If P(A) = 0.40, P(B) = 0.30 and P(A n B) = 0.12, then A and B are:

independent events

When Cynthia goes to a grocery store, there are three simple events: buy nothing, buy a small amount, or buy a large amount. In this situation, if Cynthia buys a small amount, she cannot also buy a large amount or buy nothing. Thus the three events are:

mutually exclusive