Exam 5: Discrete Probability Distributions

Studies have shown that bats can consume an average of 10 mosquitoes per minute.What is the probability that a bat does not consume any mosquitoes in a 30-second interval?

An urn is filled with three different colors of balls: red,blue,and white.There are three red balls,seven blue balls,and five white balls.If four balls are drawn,what is the probability of drawing two blue balls?

A risk-averse consumer demands a(n)_______ expected gain as compensation for taking risk.

The following table shows the number of students who did not attend statistics class over the 30 class meetings last semester. What is the expected number of absent students per class for the next semester?

A telemarketer knows that,on average,he is able to make three sales in a 30-minute period.Suppose the number of sales he can make in a given time period is Poisson distributed. a.What is the probability that he makes exactly four sales in a 30-minute period? b.What is the probability that he makes at least two sales in a 30-minute period? c.What is the probability that he makes five sales in an hour-long period?

The equation used to calculate binomial probabilities relies on permutations of n objects selected x at a time.

Thirty percent of the CFA candidates have a degree in economics.A random sample of three CFA candidates is selected.What is the probability that at least one of them has a degree in economics?

It is known that 10% of the calculators shipped from a particular factory are defective.What is the probability that at least one in a random sample of four calculators is defective?

Forty-four percent of consumers with credit cards carry balances from month to month.Four consumers with credit cards are randomly selected.What is the probability that fewer than two consumers carry a credit card balance?

On a particular production line,the likelihood that a light bulb is defective is 5%.Ten light bulbs are randomly selected.What are the mean and variance of the number of defective bulbs?

A bank manager estimates that an average of two customers enters the tellers' queue every five minutes.Assume that the number of customers that enters the tellers' queue is Poisson distributed.What is the probability that at least two customers enter the queue in a randomly selected five-minute period?

There are currently 18 pit bulls at the pound.Of the 18 pit bulls,four have attacked another dog in the last year.Joe,a member of the staff,randomly selects six of the pit bulls for his group.What is the probability that at least one of the pit bulls in Joe's group attacked another dog last year?

Consider the following probability distribution. The variance is ____.

The number of cars sold by a car salesperson during each of the last 25 weeks is the following: What is the probability that the salesperson sells no more than one car during a week?

Testing whether the computer is infected or not would be best described using binomial probability distribution.

According to a study by the Centers for Disease Control and Prevention,about 33% of U.S.births are Caesarean deliveries.Suppose seven expectant mothers are randomly selected.What is the standard deviation of the number of mothers who will have a Caesarean delivery?

An Excel's function _________ is used for calculating Poisson probabilities.

Chauncey Billups,a current shooting guard for the Los Angeles Clippers,has a career free-throw percentage of 89.4%.Suppose he shoots six free throws in tonight's game.What is the expected number of free throws that Billups will make?

According to geologists,the San Francisco Bay Area experiences five earthquakes with a magnitude of 6.5 or greater every 100 years.What is the probability that one or more earthquakes with a magnitude of 6.5 or greater will strike the San Francisco Bay Area in the next year?