Question 1

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

Accepted Answer

A) True 
 B)False

Question 2

The Post Office has established a record in a major midwestern city for delivering 90 percent of its local mail the next working day.If you mail eight local letters,what is the probability that all of them will be delivered the next day?

Accepted Answer

A) 1.0 
B) .4305 
C) .8131 
D) .5695 
A) 1.0 
B) .4305 
C) .8131 
D) .5695

Question 3

Historical data show that the average number of patient arrivals at the intensive care unit of General Hospital is 3 patients every 2 hours.Assume that the patient arrivals are distributed according to a Poisson distribution.Determine the probability of at least 4 but no more than 8 patients arriving in a three-hour period.

Accepted Answer

A) .3813 
B) .5711 
C) .4276 
D) .7861 
E) .6174 
A) .3813 
B) .5711 
C) .4276 
D) .7861 
E) .6174

Question 4

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

Accepted Answer

A) Binomial 
B) Formula 
C) Poisson 
D) Hypergeometric 
A) Binomial 
B) Formula 
C) Poisson 
D) Hypergeometric

Question 5

A large disaster cleaning company estimates that 30 percent of the jobs it bids on are finished within the bid time.Looking at a random sample of 8 jobs that it has contracted,calculate the mean number of jobs completed within the bid time.

Accepted Answer

A) 4.0 
B) 2.4 
C) 2.0 
D) 5.6 
A) 4.0 
B) 2.4 
C) 2.0 
D) 5.6

Question 6

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 more than 1 bankruptcy occurs next month.

Accepted Answer

A) .1931 
B) .9257 
C) .7326 
D) .4816 
E) .2674 
A) .1931 
B) .9257 
C) .7326 
D) .4816 
E) .2674

Question 7

For a binomial process,the probability of success is 40 percent and the number of trials is 5.Find the variance.

Accepted Answer

A) 5.0 
B) 1.2 
C) 2.0 
D) 1.1 
A) 5.0 
B) 1.2 
C) 2.0 
D) 1.1

Question 8

The standard deviation of a discrete random variable measures the spread of the population of all possible values of x.

Accepted Answer

A) True 
 B)False

Question 9

An important part of the customer service responsibilities of a cable company relates to the speed with which trouble in service can be repaired.Historically,the data show that the likelihood is 0.75 that troubles in a residential service can be repaired on the same day.For the first five troubles reported on a given day,what is the probability that at least three troubles will be repaired on the same day?

Accepted Answer

A) .1035 
B) .0376 
C) .9624 
D) .8965 
A) .1035 
B) .0376 
C) .9624 
D) .8965

Question 10

A test has 6 multiple choice questions,each with 4 alternatives.What is the probability of guessing 5 or more questions correctly?

Accepted Answer

A) .5340 
B) .4660 
C) .9954 
D) .0046 
A) .5340 
B) .4660 
C) .9954 
D) .0046

Question 11

Suppose you randomly select 3 DVDs from a production run of 10.Of the 10 DVDs,9 are expected to last a minimum of 3 years.What values of x are within two standard deviations of the mean?

Accepted Answer

The answer of Suppose you randomly select 3 DVDs from...

Question 12

An important part of the customer service responsibilities of a cable company relates to the speed with which trouble in service can be repaired.Historically,the data show that the likelihood is 0.75 that troubles in a residential service can be repaired on the same day.For the first five troubles reported on a given day,what is the probability that fewer than two troubles will be repaired on the same day?

Accepted Answer

A) .6328 
B) .0010 
C) .0156 
D) .0146 
A) .6328 
B) .0010 
C) .0156 
D) .0146

Question 13

If x is a Poisson random variable with a mean of 10,what is the probability that x is equal to 8?

Accepted Answer

A) .1126 
B) .1251 
C) .2677 
D) .0993 
A) .1126 
B) .1251 
C) .2677 
D) .0993

Question 14

Which of the following distributions can be used to solve the following problem? The average number of cars arriving at a drive-through fast-food restaurant is three in 10 minutes.What is the probability that exactly 4 cars will arrive in a five-minute interval?

Accepted Answer

A) Binomial 
B) Poisson 
C) Both of these 
D) None of these 
A) Binomial 
B) Poisson 
C) Both of these 
D) None of these

Question 15

Given that x is the yearly proportional return for stock G and y is the yearly proportional return for stock H,μx = .16,μy = .07,σx = .11,σy = .11,and σxy2 = .0321.Find the mean and standard deviation of the portfolio return: P = .5x + .5y.

Accepted Answer

Mean = .11

Question 16

Suppose you randomly select 3 DVDs from a production run of 10.Of the 10 DVDs,9 are expected to last a minimum of 3 years.What is the probability that all 3 of your DVDs will last at least three years?

Accepted Answer

The answer of Suppose you randomly select 3 DVDs from...

Question 17

A fair die is rolled 10 times.What is the average number of even number outcomes?

Accepted Answer

A) 3 
B) 4 
C) 5 
D) 6 
E) 7 
A) 3 
B) 4 
C) 5 
D) 6 
E) 7

Question 18

Two characteristics,or assumptions,of the Poisson distribution are:

Accepted Answer

A) The probability of success remains constant from trial to trial,and the random variable of interest is continuous. 
B) The event occurring in one interval is independent of the event occurring in any other nonoverlapping interval,and the random variable of interest is continuous. 
C) The event occurring in one interval is independent of the event occurring in any other nonoverlapping interval,and the random variable of interest is discrete. 
D) The event occurring in one interval is dependent on the event occurring in any other nonoverlapping interval,and the random variable of interest is continuous. 
A) The probability of success remains constant from trial to trial,and the random variable of interest is continuous. 
B) The event occurring in one interval is independent of the event occurring in any other nonoverlapping interval,and the random variable of interest is continuous. 
C) The event occurring in one interval is independent of the event occurring in any other nonoverlapping interval,and the random variable of interest is discrete. 
D) The event occurring in one interval is dependent on the event occurring in any other nonoverlapping interval,and the random variable of interest is continuous.

Question 19

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.

Accepted Answer

A) .0000 
B) .0014 
C) .0148 
D) .4997 
A) .0000 
B) .0014 
C) .0148 
D) .4997

Question 20

A random variable that is defined to be the total number of successes in n trials is a __________ random variable.

Accepted Answer

A) Binomial 
B) Poisson 
C) Hypergeometric 
D) Continuous 
A) Binomial 
B) Poisson 
C) Hypergeometric 
D) Continuous

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

The Post Office has established a record in a major midwestern city for delivering 90 percent of its local mail the next working day.If you mail eight local letters,what is the probability that all of them will be delivered the next day?

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

A large disaster cleaning company estimates that 30 percent of the jobs it bids on are finished within the bid time.Looking at a random sample of 8 jobs that it has contracted,calculate the mean number of jobs completed within the bid time.

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 more than 1 bankruptcy occurs next month.

For a binomial process,the probability of success is 40 percent and the number of trials is 5.Find the variance.

The standard deviation of a discrete random variable measures the spread of the population of all possible values of x.

A test has 6 multiple choice questions,each with 4 alternatives.What is the probability of guessing 5 or more questions correctly?

Suppose you randomly select 3 DVDs from a production run of 10.Of the 10 DVDs,9 are expected to last a minimum of 3 years.What values of x are within two standard deviations of the mean?

If x is a Poisson random variable with a mean of 10,what is the probability that x is equal to 8?

Which of the following distributions can be used to solve the following problem? The average number of cars arriving at a drive-through fast-food restaurant is three in 10 minutes.What is the probability that exactly 4 cars will arrive in a five-minute interval?

Given that x is the yearly proportional return for stock G and y is the yearly proportional return for stock H,μ_x = .16,μ_y = .07,σ_x = .11,σ_y = .11,and σ_xy² = .0321.Find the mean and standard deviation of the portfolio return: P = .5x + .5y.

Suppose you randomly select 3 DVDs from a production run of 10.Of the 10 DVDs,9 are expected to last a minimum of 3 years.What is the probability that all 3 of your DVDs will last at least three years?

A fair die is rolled 10 times.What is the average number of even number outcomes?

Two characteristics,or assumptions,of the Poisson distribution are:

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.

A random variable that is defined to be the total number of successes in n trials is a __________ random variable.

An Introduction to Business Statistics

Descriptive Statistics: Tabular and Graphical Methods

Descriptive Statistics: Numerical Methods

Probability

Continuous Random Variables

Sampling and Sampling Distributions

Confidence Intervals

Hypothesis Testing

Statistical Inferences Based on Two Samples

Experimental Design and Analysis of Variance

Chi-Square Tests

Simple Linear Regression Analysis

Multiple Regression and Model Building

Process Improvement Using Control Charts

Filters

Exam 5: Discrete Random Variables

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

The Post Office has established a record in a major midwestern city for delivering 90 percent of its local mail the next working day.If you mail eight local letters,what is the probability that all of them will be delivered the next day?

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

A large disaster cleaning company estimates that 30 percent of the jobs it bids on are finished within the bid time.Looking at a random sample of 8 jobs that it has contracted,calculate the mean number of jobs completed within the bid time.

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 more than 1 bankruptcy occurs next month.

For a binomial process,the probability of success is 40 percent and the number of trials is 5.Find the variance.

The standard deviation of a discrete random variable measures the spread of the population of all possible values of x.

A test has 6 multiple choice questions,each with 4 alternatives.What is the probability of guessing 5 or more questions correctly?

Suppose you randomly select 3 DVDs from a production run of 10.Of the 10 DVDs,9 are expected to last a minimum of 3 years.What values of x are within two standard deviations of the mean?

If x is a Poisson random variable with a mean of 10,what is the probability that x is equal to 8?

Which of the following distributions can be used to solve the following problem? The average number of cars arriving at a drive-through fast-food restaurant is three in 10 minutes.What is the probability that exactly 4 cars will arrive in a five-minute interval?

Given that x is the yearly proportional return for stock G and y is the yearly proportional return for stock H,μx = .16,μy = .07,σx = .11,σy = .11,and σxy2 = .0321.Find the mean and standard deviation of the portfolio return: P = .5x + .5y.

Suppose you randomly select 3 DVDs from a production run of 10.Of the 10 DVDs,9 are expected to last a minimum of 3 years.What is the probability that all 3 of your DVDs will last at least three years?

A fair die is rolled 10 times.What is the average number of even number outcomes?

Two characteristics,or assumptions,of the Poisson distribution are:

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.

A random variable that is defined to be the total number of successes in n trials is a __________ random variable.

An Introduction to Business Statistics

Descriptive Statistics: Tabular and Graphical Methods

Descriptive Statistics: Numerical Methods

Probability

Continuous Random Variables

Sampling and Sampling Distributions

Confidence Intervals

Hypothesis Testing

Statistical Inferences Based on Two Samples

Experimental Design and Analysis of Variance

Chi-Square Tests

Simple Linear Regression Analysis

Multiple Regression and Model Building

Process Improvement Using Control Charts

Filters

Given that x is the yearly proportional return for stock G and y is the yearly proportional return for stock H,μ_x = .16,μ_y = .07,σ_x = .11,σ_y = .11,and σ_xy² = .0321.Find the mean and standard deviation of the portfolio return: P = .5x + .5y.