Exam 5: Discrete Probability Distributions

The following table shows part of the probability distribution for a random variable x. a.The mean of the above distribution is known to be 1.8 . b.Compute the variance and the standard deviation for the above probability distribution.

Exhibit 5-2 The student body of a large university consists of 60% female students. A random sample of 8 students is selected. -Refer to Exhibit 5-2. What is the probability that among the students in the sample exactly two are female?

The number of bad checks received per day by a store and the respective probabilities are shown below. a.What is the expected number of bad checks received per day? b.Determine the variance in the number of bad checks received per day. c.What is the standard deviation?

A description of the distribution of the values of a random variable and their associated probabilities is called a

Exhibit 5-11 A local bottling company has determined the number of machine breakdowns per month and their respective probabilities as shown below: -Refer to Exhibit 5-11. The expected number of machine breakdowns per month is

Which of the following is not a characteristic of an experiment where the binomial probability distribution is applicable?

Exhibit 5-5 Probability Distribution -Refer to Exhibit 5-5. The expected value of x equals

The expected value of a discrete random variable

The Poisson probability distribution is a

In the textile industry, a manufacturer is interested in the number of blemishes or flaws occurring in each 100 feet of material. The probability distribution that has the greatest chance of applying to this situation is the

Exhibit 5-8 The random variable x is the number of occurrences of an event over an interval of ten minutes. It can be assumed that the probability of an occurrence is the same in any two-time periods of an equal length. It is known that the mean number of occurrences in ten minutes is 5.3. -Refer to Exhibit 5-8. The probability that there are 8 occurrences in ten minutes is

Which of the following is not a required condition for a discrete probability function?

In a binomial experiment

Exhibit 5-6 A sample of 2,500 people was asked how many cups of coffee they drink in the morning. You are given the following sample information. -Refer to Exhibit 5-6. The expected number of cups of coffee is

The random variable x has the following probability distribution: a.Is this probability distribution valid? Explain and list the requirements for a valid probability distribution. b.Calculate the expected value of x. c.Calculate the variance of x. d.Calculate the standard deviation of x.

The probability function for the number of insurance policies John will sell to a customer is given by f(X) = .5 - (X/6) for X = 0, 1, or 2 a.Is this a valid probability function? Explain your answer. b.What is the probability that John will sell exactly 2 policies to a customer? c.What is the probability that John will sell at least 2 policies to a customer? d.What is the expected number of policies John will sell? e.What is the variance of the number of policies John will sell?

Fifty-five percent of the applications received for a particular credit card are accepted. Among the next twelve applications, a.what is the probability that all will be rejected? b.what is the probability that all will be accepted? c.what is the probability that exactly 4 will be accepted? d.what is the probability that fewer than 3 will be accepted? e.Determine the expected number and the variance of the accepted applications.

Exhibit 5-5 Probability Distribution -Refer to Exhibit 5-5. The variance of x equals

The probability distribution of the daily demand for a product is shown below. a.What is the expected number of units demanded per day? b.Determine the variance and the standard deviation.

An experiment consists of making 80 telephone calls in order to sell a particular insurance policy. The random variable in this experiment is a