DLP projectors are used in the majority of cinema projection systems and require a
special light bulb to display a picture. Assume that the average life of a DLP bulb is
2,000 hours and that this failure time follows the exponential distribution. What is the
probability that a randomly selected bulb will last more than 2,500 hours?
A) 0.1365
B) 0.2031
C) 0.2865
D) 0.4492
The Dean of the Business School at State University would like to test the hypothesis
that no difference exists between the average final exam grades for the Introduction to
Marketing course and the Introduction to Finance course. A random sample of eight
students who took both courses was selected and their final exam grades for each
course are shown below.
If Population 1 is defined as the Marketing exam scores and Population 2 is defined as
the Finance exam scores, which one of the following statements is true?
A) Because the 95% confidence interval does include zero, we cannot conclude that a
difference exists between the average final exam grades for the Introduction to
Marketing course and the Introduction to Finance course.
B) Because the 95% confidence interval does not include zero, we can conclude that a
difference exists between the average final exam grades for the Introduction to
Marketing course and the Introduction to Finance course.
C) Because the 95% confidence interval includes zero, we cannot conclude that no
difference exists between the average final exam grades for the Introduction to
Marketing course and the Introduction to Finance course.
D) Because the 95% confidence interval includes zero, we can conclude that no
difference exists between the average final exam grades for the Introduction to
Marketing course and the Introduction to Finance course.
Sony would like to test the hypothesis that the median age of a PlayStation user is
different from the median age of an Xbox user. The following table shows the ages of a
random sample of PlayStation and Xbox users.
The test statistic for this hypothesis test is ________.
A) 69.5
B) 78.0
C) 100.5
D) 106.5
Suppose Pepsi wants to perform a blind taste test to determine if people prefer Pepsi
Max or Pepsi One. The following table shows the preferences of a random sample of
adults.
The appropriate nonparametric procedure for this analysis is the _________________
test.
A) Wilcoxon rank-sum
B) sign
C) Wilcoxon signed-rank
D) Kruskal-Wallis
Dawson’s is a fruit and vegetable stand in southern New Jersey that is considering an
expansion of the facility to take advantage of increased future demand. The future
demand for the business will be strong or weak with a 50/50 chance of each. The
following decision table summarizes Dawson’s options and the associated payoffs.
Dawson’s has the option to hire a market research firm to conduct a survey to better
ascertain the demand for their business. The cost of the survey is $5,000. Dawson’s
estimates there is a 54% chance that the survey will predict a strong demand and a 46%
that the survey will predict a weak demand. If the results of the survey predict a strong
demand, the probability of a strong demand is 70%. If the results of the survey predict a
weak demand, the probability of a strong demand is 26%.
A) Construct a decision tree to determine Dawson’s course of action.
B) What is the most that Dawson’s should pay for the survey?
YouTube would like to test the hypothesis that the standard deviation for the length of
an online video watched by a user is more than 2 minutes. A random sample of 21
people who watched online videos was selected. The sample standard deviation for the
length of the video was found to be 2.5 minutes. The test statistic for this hypothesis test
would be ________.
A) 4.66
B) 10.19
C) 22.60
D) 31.25
Suppose Bank of America (B of A) would like to investigate if credit score and income
level of an individual are independent of one another. B of A selected a random sample
of 400 adults and asked them to report their credit score range and their income range.
The following contingency table presents these results.
Using α = 0.01, the critical value for this hypothesis test is ________.
A) 9.488
B) 12.592
C) 13.277
D) 16.812
Soffritto Italian Grill served 220 dinners last Saturday night. The Chef’s Special was
ordered by 15% of the customers. A random sample of 50 customer orders from that
evening was selected. What is the probability that between 8 and 12 of these orders
were the Chef’s Special?
A) 0.3912
B) 0.5210
C) 0.7418
D) 0.8267
Sarah is the office manager for a group of financial advisors who provide financial
services for individual clients. She would like to investigate whether a relationship
exists between the number of presentations made to prospective clients in a month and
the number of new clients per month. The following table shows the number of
presentations and corresponding new clients for a random sample of six employees.
Sarah would like to use simple regression analysis to estimate the number of new
clients per month based on the number of presentations made by the employee per
month. The 90% confidence interval for the regression slope is ________.
A) (0.178, 0.431)
B) (0.052, 0.557)
C) (-0.100, 0.709)
D) (-0.235, 0.843)
Deanna has been hired to visit the local shopping mall to conduct a survey about the
upcoming political election. She needs to select respondents at the mall and ask them
questions about their voting tendencies. Deanna decides to randomly select four stores
in the mall and then approach each shopper in these stores and ask them to participate
in the survey. Which of the following sampling techniques best describes Deanna’s
method?
A) cluster
B) convenience
C) simple random
D) stratified
Edmunds.com would like to test the hypothesis that the standard deviation for the age
of an imported car on the road is greater than the standard deviation for the age of a
domestic car. The following data shows the ages of a random sample of import and
domestic cars.
Using α = 0.05, the conclusion for this hypothesis test would be that because the test
statistic is ________________________________.
A) more than the critical value, we can reject the null hypothesis and conclude that the
standard deviation for the age of an imported car on the road is greater than the standard
deviation for the age of a domestic car
B) more than the critical value, we reject the null hypothesis and cannot conclude that
the standard deviation for the age of an imported car on the road is greater than the
standard deviation for the age of a domestic car
C) less than the critical value, we can reject the null hypothesis and conclude that the
standard deviation for the age of an imported car on the road is greater than the standard
deviation for the age of a domestic car
D) less than the critical value, we fail to reject the null hypothesis and cannot conclude
that the standard deviation for the age of an imported car on the road is greater than the
standard deviation for the age of a domestic car
Use the following information to answer the question(s) below.
The National Football League has developed a regression model to predict the number
of wins during a season for a team using the following independent variables:
•Average points per game during the season (PPG)
•Average number of penalties committed per game during the season (PEN)
•Turnover differential during the season (TO)
Turnover differential is defined as the number of times the team took the ball away from
their opponent with a turnover minus the number of times the team gave the ball away to
their opponent with a turnover. For example, if TO = +5, the team had five more
takeaways than giveaways. If TO = “7, the team had seven more giveaways than
takeaways during the season.
The following Excel output shows the partially completed regression output from a
random season.
The critical value for the hypothesis test for the overall regression model using α = 0.05 is
________.
A) 2.596
B) 2.947
C) 3.256
D) 5.197
The table below shows the number of cars sold last month by seven employees at
Concord Motors and their number of years of sales experience.
Management would like to use simple regression analysis to estimate monthly car sales
using the number of years of sales experience. The 95% confidence interval for the
regression slope is ________.
A) (“1.842, 3.158
B) (“0.481, 1.797)
C) (0.058, 1.258)
D) (0.408, 0.908)
________ represent the seasonal and random components in the original time series and
is found by dividing the time series value by its centered moving average.
A) Seasonal factors
B) Ratio-to-moving-averages
C) Normalized seasonal factors
D) Deseasonalized trend components
In Delaware, cars are inspected each year using state-operated inspection centers. The
Wilmington center has three drive-through lanes where cars are inspected in a sequence
of steps. The following data show the number of minutes that a random sample of
drivers spent waiting and having their cars inspected in the three lanes each day of the
week.
The state of Delaware would like to perform a randomized block ANOVA to test for a
difference in the average times the drivers spend in the three lanes using the weekday as
a blocking factor with α = 0.05. The conclusion for this hypothesis test would be that
because the main factor test statistic is
___________________________________________________________________,
A) less than the main factor critical value, we can conclude that there is a difference in
the average number of minutes drivers spend between these three inspection lanes
B) less than the main factor critical value, we can conclude that there is no difference in
the average number of minutes drivers spend between these three inspection lanes
C) more than the main factor critical value, we can conclude that there is a difference in
the average number of minutes drivers spend between these three inspection lanes
D) more than the main factor critical value, we can conclude that there is no difference
in the average number of minutes drivers spend between these three inspection lanes
According to the National Health Interview Survey, 4.7% of U.S. adults 50 and older
have had a total knee replacement. A random sample of 20 adults 50 and older has been
selected. Use the Poisson distribution to approximate the binomial distribution to
determine the probability that three or four adults from this sample have had a total
knee replacement.
A) 0.0668
B) 0.1145
C) 0.2553
D) 0.4219
The following table shows the frequency distribution of the credit scores for a random
sample of homeowners who recently refinanced their mortgage at Delaware Bank.
Calculating the probability that a randomly homeowner has a credit score of 760 to
under 780 is using ________ probability.
A) classical
B) simple
C) empirical
D) subjective
According to R.L. Polk & Co., Americans held onto their new vehicles for an average
of 71.4 months. A random sample of 60 adults who recently sold their new vehicle was
selected. Assuming the standard deviation for this population is 15.8 months, the
standard error for this sample is ________.
A) 1.30
B) 2.04
C) 3.56
D) 5.92
A(n) ________ in ANOVA describes a category within the factor of interest.
A) error rate
B) level
C) block
D) factor
________________ statistics describe procedures that assume that the population from
which the sample is drawn follows a known probability distribution.
A) Nonparametric
B) Descriptive
C) Parametric
D) Quantitative
Jeff sells the New York Times Sunday newspaper at a city corner near several churches.
He sells each newspaper for $6.50 after purchasing them for $4.00. Any unsold
newspaper can be returned to the New York Times for a $0.75 credit. Jeff expects
demand on Sunday to be 75, 100, 125, or 150 newspapers and would like to order one
of these four quantities from the New York Times. If the Jeff uses the Hurwicz criterion
with , how many newspapers will he order?
A) 75
B) 100
C) 125
D) 150
Edmunds.com would like to test the hypothesis that the standard deviation for the age
of an imported car on the road is greater than the standard deviation for the age of a
domestic car. The following data shows the ages of a random sample of import and
domestic cars.
The standard deviation for the age of domestic cars would be ________.
A) 0.90
B) 2.15
C) 3.78
D) 5.03
The federal government would like to test the hypothesis that the median age of men
filing for Social Security is higher than the median age of women set using α = 0.05
with the following sample data:
The lower and upper critical values for this hypothesis test using are
________.
A) 49, 87
B) 51, 93
C) 43, 76
D) 41, 71
A random sample of 60 business students required an average of 50.7 minutes to
complete a statistics exam. Assume that the population standard deviation to complete
the exam was 10.4 minutes. The 98% confidence interval around this sample mean is
________.
A) (47.6, 53.8)
B) (49.8, 51.6)
C) (48.9, 52.5)
D) (45.4, 56.0)
Which of the following probability distribution is not continuous?
A) Poisson
B) normal
C) exponential
D) All of these are continuous probability distributions.
The _________________________ test determines whether two populations have the
same probability distribution based on evidence from two independent samples.
A) Wilcoxon rank-sum
B) sign
C) Wilcoxon signed-rank
D) Kruskal-Wallis
Consider the following data set:
Variable 1:
Variable 2:
The sample covariance for this data set is
A) “15.57
B) “10.31
C) 3.40
D) 12.19
Data that describe a characteristic about a population is known as a ________.
A) sample
B) survey
C) statistic
D) parameter
The Canadian government would like to test the hypothesis that the standard deviation
for the hourly wage for men is equal to the standard deviation for the hourly wage for
women. The following data summarizes the sample statistics for hourly wages for men
and women.
Using α = 0.05, the conclusion for this hypothesis test would be that because the test
statistic is _________________________________.
A) more than the critical value, we fail to reject the null hypothesis and conclude that
the standard deviation for the hourly wage for men is equal to the standard deviation for
the hourly wage for women
B) more than the critical value, we can reject the null hypothesis and conclude that the
standard deviation for the hourly wage for men is not equal to the standard deviation for
the hourly wage for women
C) less than the critical value, we reject the null hypothesis and conclude that the
standard deviation for the hourly wage for men is not equal to the standard deviation for
the hourly wage for women
D) less than the critical value, we fail to reject the null hypothesis and cannot conclude
that the standard deviation for the hourly wage for men is not equal to the standard
deviation for the hourly wage for women
When outliers are present in the data set, the ________ is the best choice to measure
central tendency.
A) mean
B) median
C) mode
D) standard deviation
Recently, the average amount of time to foreclose on a house in the U.S. was reported
to be 359 days. Assume that the standard deviation for this population is 90.4 days. A
random sample of 42 homes that have completed the foreclosure process was selected.
What is the probability that the sample average was less than 375 days?
A) 0.5129
B) 0.6350
C) 0.7264
D) 0.8749
YouTube would like to test the hypothesis that the standard deviation for the length of
an online video watched by a user is more than 2 minutes. A random sample of 21
people who watched online videos was selected. The sample standard deviation for the
length of the video was found to be 2.5 minutes. Using α = 0.10, the critical value for
this hypothesis test would be ________.
A) 12.443
B) 28.412
C) 29.615
D) 30.813
Assume that the amount of time that it takes an employee to service a car at an oil
change facility follows the uniform probability distribution between 21 and 38 minutes.
What is the probability that a randomly selected car will require exactly 30 minutes to
service?
A) 0.0
B) 0.2565
C) 0.4706
D) 0.5894
Use the information below to answer the following question(s).
The Marseille Water Taxi ferries tourists from the harbor at Marseille, France, to the
Frioul Islands in the Mediterranean Sea. The table below shows the number of
passengers on the noontime ferry over seven randomly selected days along with the
current ambient temperature in degrees Celsius.
Use the Marseille Water Taxi data to:
A) Describe the regression line that will predict the number of passengers on the
noontime ferry based on the ambient temperature.
B) Interpret the slope of the regression equation.
C) Predict number of passengers on the noontime ferry on a day that the ambient
temperature is 19 degrees Celsius.