Exam 4: A Survey of Probability Concepts

You take a trip by air that involves three independent flights. If there is a 90 percent chance each specific leg of the trip is done on time, what is the probability all three flights arrive on time?

A study was done of the 377 vehicles parked in the college parking lot last Friday. The results follow. What is the probability of finding a red car?

The result of a particular experiment is called a(n)

According to which classification or type of probability are the events equally likely?

Each salesperson in a large department store chain is rated with respect to sales potential for advancement. These traits for the 500 salespeople were cross-classified into the following table: What is the probability that the selected salesperson has below average sales ability?

A lamp manufacturer has developed five lamp bases and four lampshades that could be used together. How many different arrangements of base and shade can be offered?

i. A probability is usually expressed as a decimal, such as 0.70 or 0.27, but it may be given as a fraction, such as 7/10 or 27/100. ii. The closer a probability is to 0, the more likely that an event will happen. iii. The closer the probability is to 1.00, the more likely an event will not happen.

i. The Cunard luxury liner, Queen Elizabeth 2, cannot be docked in Hong Kong and Bangkok at the same time. Events such as these that cannot occur simultaneously are said to be collectively exhaustive. ii. If there are 'm' ways of doing one thing and 'n' ways of doing another thing, the multiplication formula states that there are (m)(n) ways of doing both. iii. A permutation is an arrangement of a set of objects in which there is an order from the first through the last.

The customer service department of H&R Block received a total of 235 telephone requests for a tip-sheet on personal tax or corporate tax. The following table summarizes callers' primary area of interest, and how they first heard about the tip-sheet. What is the probability a caller became aware of the tip-sheet either by radio or newspaper given her primary interest is corporate tax?

i. The complement rule states that the probability of an event not occurring is equal to one minus the probability of its occurrence. ii. If there are two independent events A and B, the probability that A and x B will occur is found by multiplying the two probabilities. Thus for two events A and B, the special rule of multiplication shown symbolically is: P(A and B) = P(A) P(B). iii. The general rule of multiplication is used to find the joint probability that two events will occur. Symbolically, the joint probability P(A and B) is found by: P(A and B) = P(A)P(B/A).

There are 10 rolls of film in a box and 3 are defective. Two rolls are to be selected one after the other. What is the probability of selecting a defective roll followed by another defective roll?

Each salesperson in a large department store chain is rated with respect to sales potential for advancement. These traits for the 500 salespeople were cross classified into the following table. What is the probability that a salesperson selected at random will have below average sales ability and fair potential for advancement?

Considering the chart below, what is the probability that if you select one person at random that they have committed a violent crime?

A study of the opinion of designers with respect to the primary colour most desirable for use in executive offices showed that: What is the probability that a designer does not prefer red?

Routine physical examinations are conducted annually as part of a health service program for the employees. It was discovered that 8% of the employees needed corrective shoes, 15% needed major dental work and 3% needed both corrective shoes and major dental work. What is the probability that an employee selected at random will need either corrective shoes or major dental work?

Considering the chart below, what is the probability that if you select one person at random that they have committed a violent crime and were under 20 years of age?

In a management trainee program, 80 percent of the trainees are female, 20 percent male. Ninety percent of the females attended college, 78 percent of the males attended college. A management trainee is selected at random. What is the probability that the person selected is a female who did NOT attend college?

(i. A particular result of an experiment is called a(n) outcome. (ii) When the occurrence of one event does not affect the occurrence of the other event, the two events are independent. (iii) If the order of a set of objects is important, it is called permutation.

An electronics firm manufactures three models of stereo receivers, two cassette decks, four speakers and three CD players. When the four types of components are sold together, they form a "system." How many different systems can the electronic firm offer?

i. The probability of an event, based on a classical approach, is defined as the number of favourable outcomes divided by the total number of possible outcomes. ii. If among several events only one can occur at a time, we refer to these events as being mutually exclusive events. iii. The probability of rolling a 3 or 2 on a single die is an example of conditional probability.