Exam 2: Probability Concepts and Applications

Stating that two events are statistically independent means that the probability of one event occurring is independent of the probability of the other event having occurred.

At a university with 1,000 business majors, there are 200 business students enrolled in an introductory statistics course.Of these 200 students, 50 are also enrolled in an introductory accounting course.There are an additional 250 business students enrolled in accounting but not enrolled in statistics.If a business student is selected at random, what is the probability that the student is enrolled in accounting?

In a normal distribution, the Z value represents the number of standard deviations from a value X to the mean.

Saying that a set of events is mutually exclusive and collectively exhaustive implies that one and only one of the events can occur on any trial.

Fast Service Store has maintained daily sales records on the various size "Cool Drink" sales. Assuming that past performance is a good indicator of future sales, (a)What is the probability of a customer purchasing a $1.00 "Cool Drink?" (b)What is the probability of a customer purchasing a $1.25 "Cool Drink?" (c)What is the probability of a customer purchasing a "Cool Drink" that costs greater than or equal to $1.00? (d)What is the expected value of a "Cool Drink"? (e)What is the variance of a "Cool Drink"?

The number of bad checks written at a local store is an example of a discrete random variable.

A new young executive is perplexed at the number of interruptions that occur due to employee relations.She has decided to track the number of interruptions that occur during each hour of her day.Over the last month, she has determined that between 0 and 3 interruptions occur during any given hour of her day.The data is shown below. On average, she should expect 1.0 interruptions per hour.

Disco Fever is randomly found in one half of one percent of the general population.Testing a swatch of clothing for the presence of polyester is 99% effective in detecting the presence of this disease.The test also yields a false-positive in 4% of the cases where the disease is not present.What is the probability that the test result is positive?

Subjective probability implies that we can measure the relative frequency of the values of the random variable.

Disco Fever is randomly found in one half of one percent of the general population.Testing a swatch of clothing for the presence of polyester is 99% effective in detecting the presence of this disease.The test also yields a false-positive in 4% of the cases where the disease is not present.What is the probability that the disease is present if the test result is positive?

In a given office, the color printer breaks down with a probability of 20% in any month.A binomial process is assumed for a period of 10 months. (a)What is the probability that the printer breaks down exactly 2 times? (b)What is the probability that the printer breaks down at most 1 time? (c)What is the probability that the printer breaks down more than once?

Suppose that, historically, April has experienced rain and a temperature between 35 and 50 degrees on 20 days.Also, historically, the month of April has had a temperature between 35 and 50 degrees on 25 days.You have scheduled a golf tournament for April 12.If the temperature is between 35 and 50 degrees on that day, what will be the probability that the players will get wet?

A production process is known to produce a particular item in such a way that 5 percent of these are defective.If two items are randomly selected as they come off the production line, what is the probability that both are defective (assuming that they are independent)?

The number of cars passing through an intersection in the next five minutes can usually be described by the

At a university with 1,000 business majors, there are 200 business students enrolled in an introductory statistics course.Of these 200 students, 50 are also enrolled in an introductory accounting course.There are an additional 250 business students enrolled in accounting but not enrolled in statistics.If a business student is selected at random, what is the probability that the student is enrolled in statistics?

The joint probability of two or more independent events occurring is the sum of their marginal or simple probabilities.

Which of the following characteristics is not true for the exponential distribution?

A consulting firm has received 2 Super Bowl playoff tickets from one of its clients.To be fair, the firm is randomly selecting two different employee names to "win" the tickets.There are 6 secretaries, 5 consultants, and 4 partners in the firm.Which of the following statements is true?

A random variable

Disco Fever is randomly found in one half of one percent of the general population.Testing a swatch of clothing for the presence of polyester is 99% effective in detecting the presence of this disease.The test also yields a false-positive in 4% of the cases where the disease is not present.What is the probability that the disease is not present in any particular person?