Question 1

Suppose that x has a hypergeometric distribution with N = 10,r = 5,and n = 3.Calculate the mean of the distribution.

Accepted Answer

A) 0.500 
B) 0.333 
C) 1.500 
D) 3.000 
A) 0.500 
B) 0.333 
C) 1.500 
D) 3.000

Question 2

A multiple-choice test has 30 questions and each one has five possible answers,of which one is correct.If all answers were guesses,find the probability of getting exactly four correct answers.

Accepted Answer

A) .0604 
B) .1325 
C) .2552 
D) .8000 
A) .0604 
B) .1325 
C) .2552 
D) .8000

Question 3

According to a survey of adults,64 percent have money in a regular savings account.If we were to survey 50 randomly selected adults,find the mean number of adults who would have regular savings accounts.

Accepted Answer

A) 12 
B) 22 
C) 32 
D) 42 
A) 12 
B) 22 
C) 32 
D) 42

Question 4

A vaccine is 95 percent effective.What is the probability that it is not effective for one and only one individual out of 20 individuals?

Accepted Answer

A) .0179 
B) .3585 
C) .0189 
D) .3774 
A) .0179 
B) .3585 
C) .0189 
D) .3774

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 probability that exactly 4 of the jobs were not completed within the bid time.

Accepted Answer

A) .0081 
B) .2401 
C) .0113 
D) .1361 
A) .0081 
B) .2401 
C) .0113 
D) .1361

Question 6

If the probability distribution of X is $\begin{array} { c c } 
\mathrm { X } & \mathrm { P } ( \mathrm { X } ) \
3 & 1 / 8 \
4 & 1 / 8 \
5 & 3 / 8 \
6 & 3 / 8
\end{array}$
What is the variance of X?

Accepted Answer

A) 1.0 
B) 5.0 
C) 2.25 
D) 2.24 
A) 1.0 
B) 5.0 
C) 2.25 
D) 2.24

Question 7

Determine the probability that a 3 will appear twice,if a fair die is rolled 10 times.

Accepted Answer

A) .5010 
B) .2907 
C) .2318 
D) .0065 
A) .5010 
B) .2907 
C) .2318 
D) .0065

Question 8

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 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 9

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 exactly 4 bankruptcies occur next month.

Accepted Answer

A) .8774 
B) .1414 
C) .1557 
D) .2176 
A) .8774 
B) .1414 
C) .1557 
D) .2176

Question 10

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 none of the students voted.

Accepted Answer

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

Question 11

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 12

Your company's internal auditor believes that 10 percent of the company's invoices contain errors.To check this theory,20 invoices are randomly selected and 5 are found to have errors.The auditor's claim will be rejected.

Accepted Answer

A) True 
 B)False

Question 13

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 mean of the random variable x?

Accepted Answer

2.7
Feedba

Question 14

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 15

In a study conducted for the state Department of Education,30 percent of the teachers who left teaching did so because they were laid off.Assume that we randomly select 10 teachers who have recently left their profession.Find the probability that exactly 4 of them were laid off.

Accepted Answer

A) .3000 
B) .2668 
C) .2001 
D) .0090 
A) .3000 
B) .2668 
C) .2001 
D) .0090

Suppose that x has a hypergeometric distribution with N = 10,r = 5,and n = 3.Calculate the mean of the distribution.

A multiple-choice test has 30 questions and each one has five possible answers,of which one is correct.If all answers were guesses,find the probability of getting exactly four correct answers.

According to a survey of adults,64 percent have money in a regular savings account.If we were to survey 50 randomly selected adults,find the mean number of adults who would have regular savings accounts.

A vaccine is 95 percent effective.What is the probability that it is not effective for one and only one individual out of 20 individuals?

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 probability that exactly 4 of the jobs were not completed within the bid time.

If the probability distribution of X is () 3 1/8 4 1/8 5 3/8 6 3/8 What is the variance of X?

Determine the probability that a 3 will appear twice,if a fair die is rolled 10 times.

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 exactly 4 bankruptcies occur next month.

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 none of the students voted.

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

Your company's internal auditor believes that 10 percent of the company's invoices contain errors.To check this theory,20 invoices are randomly selected and 5 are found to have errors.The auditor's claim will be rejected.

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 mean of the random variable x?

In a study conducted for the state Department of Education,30 percent of the teachers who left teaching did so because they were laid off.Assume that we randomly select 10 teachers who have recently left their profession.Find the probability that exactly 4 of them were laid off.

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

Comparing Two Means and Two Proportions

Filters

Exam 5: Discrete Random Variables

Suppose that x has a hypergeometric distribution with N = 10,r = 5,and n = 3.Calculate the mean of the distribution.

A multiple-choice test has 30 questions and each one has five possible answers,of which one is correct.If all answers were guesses,find the probability of getting exactly four correct answers.

According to a survey of adults,64 percent have money in a regular savings account.If we were to survey 50 randomly selected adults,find the mean number of adults who would have regular savings accounts.

A vaccine is 95 percent effective.What is the probability that it is not effective for one and only one individual out of 20 individuals?

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 probability that exactly 4 of the jobs were not completed within the bid time.

If the probability distribution of X is () 3 1/8 4 1/8 5 3/8 6 3/8 What is the variance of X?

Determine the probability that a 3 will appear twice,if a fair die is rolled 10 times.

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 exactly 4 bankruptcies occur next month.

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 none of the students voted.

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

Your company's internal auditor believes that 10 percent of the company's invoices contain errors.To check this theory,20 invoices are randomly selected and 5 are found to have errors.The auditor's claim will be rejected.

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 mean of the random variable x?

In a study conducted for the state Department of Education,30 percent of the teachers who left teaching did so because they were laid off.Assume that we randomly select 10 teachers who have recently left their profession.Find the probability that exactly 4 of them were laid off.

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

Comparing Two Means and Two Proportions

Filters