Exam 5: Discrete Random Variables

An insurance company will insure a $75,000 Hummer for its full value against theft at a premium of $1500 per year.Suppose that the probability that the Hummer will be stolen is 0.0075.Find the premium that the insurance company should charge if it wants its expected net profit to be $2000.

In the most recent election,19 percent of all eligible college students voted.If a random sample of 20 students were surveyed,find the probability that exactly half voted in the election.

The J.O.Supplies Company buys calculators from a Korean supplier.The probability of a defective calculator is 10 percent.If 10 calculators are selected at random,what is the probability that 3 or more of the calculators will be defective?

The mean of a hypergeometric random variable is defined as:

The variable "home ownership" can take on one of two values,1 if the person living in a home owns the home and zero if the person living in a home does not own the home.This is an example of a discrete random variable.

A car wash loses $30 on rainy days and makes $120 on days when it does not rain.If the probability of rain is 0.15,calculate the car wash's expected profit.

The mean and the variance of a Poisson random variable are equal.

Which of the following statements about the binomial distribution is not correct?

The probability distribution of a random variable that is defined to be the number of successes obtained in a random sample selected without replacement from a finite population of N elements that contains r successes and N - r failures is:

A fair die is rolled 10 times.What is the probability that an odd number (1,3,or 5)will occur fewer than 3 times?

The J.O.Supplies Company buys calculators from a Korean supplier.The probability of a defective calculator is 10 percent.If 3 calculators are selected at random,what is the probability that one of the calculators will be defective?

According to data from the state blood program,40 percent of all individuals have group A blood.If six individuals give blood,find the mean number of individuals having group A blood.

Consider the experiment of tossing a fair coin three times and observing the number of heads that result (X = number of heads).Determine the expected number of heads.

An insurance company will insure a $75,000 Hummer for its full value against theft at a premium of $1500 per year.Suppose that the probability that the Hummer will be stolen is 0.0075.Calculate the insurance company's expected net profit.

A probability distribution of a discrete random variable is expressed as a table,graph,or ___________.

The mean of the binomial distribution is np(1 - p).

A lawyer believes that the probability is .3 that she can win a discrimination suit.If she wins the case,she will make $40,000;but if she loses,she gets nothing.Assume that she has to spend $5000 preparing the case.What is her expected gain?

X has the probability distribution: () -1 .2 0 .3 1 .5 Compute the expected value of X.

A Poisson random variable is a continuous variable that can be used to describe the number of occurrences of an event over a specified interval of time or space.

The Securities and Exchange Commission has determined that the number of companies listed on the NYSE declaring bankruptcy is approximately a Poisson distribution with a mean of 2.6 per month.Find the probability that no more than one bankruptcy occurs next month.