According to the Mortgage Bankers Association, 11% of U.S. mortgages were
delinquent last year. A delinquent mortgage is one that has missed at least one payment
but has not yet gone to foreclosure. A random sample of six mortgages was selected.
What is the standard deviation of this distribution?
A) 0.402
B) 0.766
C) 0.965
D) 1.149
The ________ of a discrete probability distribution measures the dispersion of each
outcome of the random variable from the mean of the distribution.
A) standard deviation
B) median
C) expected value
D) range
The National Center for Education Statistics would like to test the hypothesis that the
proportion of Bachelor’s degrees that were earned by women equals 0.60. A random
sample of 140 college graduates with Bachelor degrees found that 75 were women. The
National Center for Education Statistics would like to set α = 0.10. The correct
hypothesis statement for this hypothesis test would be _______________________.
A)
B)
C)
D)
The federal government would like to test the hypothesis that the standard deviation for
the age of men filing for Social Security is higher than the standard deviation for the
age of women. The following table summarizes sample statistics from each population.
Using α = 0.10, 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 age of men filing for Social Security is higher than the
standard deviation for the age of women
B) more than the critical value, we can reject the null hypothesis and conclude that the
standard deviation for the age of men filing for Social Security is higher than the
standard deviation for the age of women
C) less than the critical value, we fail to reject the null hypothesis and conclude that the
standard deviation for the age of men filing for Social Security is higher than the
standard deviation for the age of women
D) less than the critical value, we fail to reject the null hypothesis and cannot conclude
that the standard deviation for the age of men filing for Social Security is higher than
the standard deviation for the age of women
Education level is an example of nominal data.
According to the Gallup Crime survey, 26% of gun owners are women. From a random
sample of 160 gun owners, 26 were female. Which of the following statements is
correct?
A) The interval that contains 95% of the sample proportions is 0.192 and 0.328.
Because the sample proportion is between these two values, we have support that the
proportion of gun owners who are female is 26%.
B) The interval that contains 95% of the sample proportions is 0.192 and 0.328.
Because the sample proportion is not between these two values, we do not have support
that the proportion of gun owners who are female is 23\6%.
C) The interval that contains 95% of the sample proportions is 0.225 and 0.295.
Because the sample proportion is between these two values, we have support that the
proportion of gun owners who are female is 26%.
D) The interval that contains 95% of the sample proportions is 0.225 and 0.295.
Because the sample proportion is not between these two values, we do not have support
that the proportion of gun owners who are female is 26%.
The following data represent the number of complaints per month that customer service
received at a large retailer over the last 15 months.
The Durbin-Watson statistic for this time series is ________.
A) 2.81
B) 3.56
C) 4.25
D) 5.88
Entertainment Software Association would like to test if the median age of “gamers”
(those that routinely play video games) is more than 30 years old. The following table
summarizes the ages of a random sample of gamers.
The standard deviation for the sampling distribution for this hypothesis test is
________.
A) 3.240
B) 3.965
C) 4.566
D) 4.817
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 mean square block for these observations is
________.
A) 135.0
B) 148.9
C) 162.6
D) 174.4
“Gamers” are described as people who regularly play video games. A random sample of
120 people was selected and 66 were found to be male. Using this sample, the point
estimate for the proportion of gamers who are male is ________.
A) 0.55
B) 0.66
C) 0.71
D) 0.75
Many franchisers favor owners who operate multiple stores by providing them with
preferential treatment. Suppose the Small Business Administration would like to
perform a hypothesis test to investigate if 80% of franchisees own only one location
using α = 0.05. A random sample of 120 franchisees found that 85 owned only one
store. The conclusion for this hypothesis test would be that because the absolute value
of the test statistic is
A) more than the absolute value of the critical value, we can conclude that the
proportion of franchisees that own only one store equals 0.80.
B) more than the absolute value of the critical value, we can conclude that the
proportion of franchisees that own only one store does not equal 0.80.
C) less than the absolute value of the critical value, we cannot conclude that the
proportion of franchisees that own only one store does not equal 0.80.
D) less than the absolute value of the critical value, we can conclude that the proportion
of franchisees that own only one store does not equal 0.80.
Suppose Burger King has run a major advertising campaign in the hopes of increasing
monthly sales. To investigate the effectiveness of this campaign, Burger King randomly
selected seven restaurants and recorded the monthly sales before and after the
advertising. The following data represents these sales figures in thousands of dollars.
If Population 1 is defined as sales after the advertising campaign and Population 2 is
defined as sales before the advertising campaign, the 90% confidence interval for the
difference in population means is ________.
A) (5.27, 8.73)
B) (2.68, 11.32)
C) (“1.70, 15.70)
D) (“5.96, 19.96)
During the 3 pm to 5 pm time period, cars arrive at a bank’s drive-through window at an
average rate of 15 customers per hour. Assume that the time between arrivals follows
the exponential distribution. What is the average time between customer arrivals?
A) 4 minutes
B) 10 minutes
C) 15 minutes
D) 30 minutes
The following data represent the wait time, in minutes, for customers calling Comcast
technical support.
The upper limit for determining outliers for a box-and-whisker plot is ________
minutes,
A) 29.5
B) 31
C) 33.5
D) 36
The unit of measure for the variance is the same as the unit of measure for the original
data.
When testing for a normal distribution with the chi-square goodness-of-fit test with a
sample size of 30 observations, the number of intervals needed to satisfy the minimum
number of expected frequencies is ________.
A) 4
B) 5
C) 6
D) The sample size is too small to perform the chi-square goodness-of-fit test.
Use the following information to answer the question(s) below.
Ford would like to develop a regression model that would predict the number of cars
sold per month by a dealership employee based on the employee’s number of years of
sales experience (Exp), the employee’s weekly base salary before commissions (Salary),
and the education level of the employee. There are three levels of education in the sales
forcehigh school degree, associate’s degree, and bachelor’s degree. The following
dummy variables have been defined.
The following Excel output shows the partially completed regression output from a
random sample of employees from the previous month.
An employee with a bachelor’s degree will average ________ more cars sales per
month than an employee with a high school degree.
A) 2.9845
B) 1.3553
C) 2.5638
D) 0.4207
A professor would like to test the hypothesis that the median number of minutes that a
student needs to complete a statistics exam is equal to 50 minutes. The following
random sample of exam times from 12 students was collected to test this hypothesis.
The p-value for this hypothesis test is ________.
A) 0.0192
B) 0.0384
C) 0.0844
D) 0.1006
Suppose the dealer incentive per vehicle for Honda’s Acura brand in 2012 is thought to
be bell-shaped and symmetrical with a mean of $2,500 and a standard deviation of
$300. Based in this information, what interval of dealer incentives would we expect
approximately 99.7% of vehicles to fall within?
A) $2,200 to $2,800
B) $1,900 to $3,100
C) $1,600 to $3,400
D) $1,300 to $3,700
Costco sells paperback books in their retail stores and wanted to examine the
relationship between price and demand. The price of a particular novel was adjusted
each week and the weekly sales were recorded in the table below.
The test statistic for testing whether the population correlation coefficient is less than
zero is ________.
A) “3.07
B) “4.39
C) “6.24
D) 4.40
The Wall Street Journal reported that the average amount of time that a French person
spends eating lunch at a restaurant is 22 minutes. Perform a hypothesis test to determine
if a difference exists between the average time an American spends eating lunch when
compared to a person from France. The following data represents the time, in minutes,
that random French and American diners spent at lunch. Assume that the population
variances are equal.
If Population 1 is defined as French diners and Population 2 is defined as American
diners, the pooled variance for this hypothesis test would be ________.
A) 10.83
B) 12.97
C) 14.25
D) 16.78
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.
The expected number of individuals with income between $50,000 and $100,000 and a
credit score less than 650 is ________.
A) 30.0
B) 32.5
C) 37.5
D) 60.0
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 standard error of the slope is
________.
A) 0.1588
B) 0.2102
C) 0.4429
D) 0.5182
An office building has four copier machines that require the administrative assistant to
replenish the paper supply when the paper bin is empty. It is believed that the need for
paper for a copier on any given day follows the binomial distribution with p = 0.50. The
following data represent the number of days that 0, 1, 2, 3, or 4 copiers needed paper
replenished from a random sample of 100 business days.
Using α = 0.10, the critical value for this hypothesis test is ________.
A) 5.991
B) 7.779
C) 9.448
D) 11.070
Sony would like to test the hypothesis that the average age of a PlayStation user is
different from the average age of an Xbox user. A random sample of 36 PlayStation
users had an average age of 34.2 years while a random sample of 30 Xbox users had an
average age of 32.7 years. Assume that the population standard deviation for the age of
PlayStation and Xbox users is 3.9 and 4.0 years, respectively. Sony would like to set α
= 0.10. If Population 1 is defined as PlayStation users and Population 2 is defined as
Xbox users, the correct hypothesis statement for this hypothesis test would be
__________________________.
A)
B)
C)
D)
The Centers for Disease Control (CDC) would like to test the hypothesis that the
proportion of obese adults in the U.S. has increased this year when compared to last
year. A random sample of 125 adults this year found that 56 were obese. Last year, a
random sample of 140 adults found that 42 were obese. If Population 1 is defined as
this year and Population 2 is defined as last year, and using α = 0.01, the critical value
for this hypothesis test would be ________.
A) 1.96
B) 1.28
C) 2.05
D) 2.33
Which one of the following is not a valid number for a probability?
A) 0.63
B) 1.50
C) 17%
D) 0
Lisa is a regional manager for a restaurant chain that has locations in the towns of
Berwick, Milton, and Leesburg. She would like to investigate if a difference exists in
the proportion of customers who rate their experience as satisfactory or better between
the three locations. The following data represent the number of customers who
indicated they were satisfied from random samples taken at each location.
The chi-square test statistic for these samples is ________.
A) 1.49
B) 2.44
C) 4.15
D) 5.33
The following data represent the number of complaints per month that customer service
received at a large retailer over the last 15 months.
Which one of the following statements is true for the hypothesis test for positive
autocorrelation using α = 0.05?
A) Because the Durbin-Watson statistic is less than the lower critical value, we fail to
reject the null hypothesis and conclude that positive autocorrelation is present in the
time series.
B) Because the Durbin-Watson statistic is less than the lower critical value, we reject
the null hypothesis and conclude that positive autocorrelation is not present in the time
series.
C) Because the Durbin-Watson statistic is greater than the upper critical value, we fail
to reject the null hypothesis and conclude that no positive autocorrelation is present in
the time series.
D) Because the Durbin-Watson statistic is greater than the lower critical value, we reject
the null hypothesis and conclude that positive autocorrelation is present in the time
series.
Many franchisers favor owners who operate multiple stores by providing them with
preferential treatment. Suppose the Small Business Administration would like to
perform a hypothesis test to investigate if 80% of franchisees own only one location
using α = 0.05. A random sample of 120 franchisees found that 85 owned only one
store. The correct hypothesis statement for this hypothesis test would be
__________________________.
A)
B)
C)
D)
Suppose the average tread-life of a certain brand of tire is 42,000 miles and that this
mileage follows the exponential probability distribution. What is the probability that a
randomly selected tire will have a tread-life of more than 40,000 miles?
A) 0.1546
B) 0.2410
C) 0.3016
D) 0.3858
Consider the partially completed randomized block ANOVA summary table.
The sum of squares block for this ANOVA procedure is ________.
A) 800
B) 930
C) 980
D) 1,150
The ________ is used to test the significance of the population coefficient of
determination.
A) normal distribution
B) Student’s t-distribution
C) F-distribution
D) chi-square distribution
Sheridan Motors is a car dealership that would like to investigate if there is a difference
in the average number of car sales per month between three sales employees using a
randomized block ANOVA. The following data represent the number of car sales last
year for these employees for six different months.
The blocking factor test statistic for this hypothesis test would be ________.
A) 5.61
B) 6.98
C) 8.17
D) 9.33
The following graph shows the average price of LCD TVs from 2005 until 2012.
This graph is an example of a ________.
A) histogram
B) vertical bar chart
C) Pareto chart
D) line chart