For a relatively large beta (closer to 1.0), the current trend adjustment is more affected
by the most recent trend when using exponential smoothing with trend adjustment.
Using the equally likely criterion you choose the alternative with the highest in the
decision table.
The central tendency is where the majority of the data points can be found in a
histogram.
When comparing models with similar adjusted values when using best
subsets regression, choose the one with the higher number of independent variables.
The F-test for the overall regression model does not tell us which of the independent
variables are statistically significant.
When testing for the significance of the overall regression model, the null hypothesis
claims that there is a relationship between the dependent and independent variables.
If the hypothesis test is to be used in an attempt to prove a particular point of view, you
would assign the null hypothesis to establish the point of view you favor.
Including a blocking factor in the ANOVA procedure can sometimes hinder the ability
to correctly detect a difference in population means.
When constructing a pie chart, all categories in the data set must be included in the pie.
The definition of a 90% confidence interval is that we expect that close to 90% of a
large number of sample means drawn from a population will produce confidence
intervals that include that population’s mean.
The values of the correlation coefficient range between -1.0 and +1.0.
A 100% confidence interval is more accurate than a 90% confidence interval and is
therefore more preferable.
The confidence interval for the mean is symmetrical around the population mean.
The expected monetary value (EMV) is the average of the payoffs associated with a
particular alternative weighted with the probabilities for each state of nature.
When the index point, i, is not a whole number, round i up to the next highest whole
number to find the position of the median in a sorted data set.
The degrees of freedom for the sum of squares within for one-way ANOVA equal the
total number of observations minus one.
Chebyshev’s Theorem only applies to bell-shaped curves that are relatively
symmetrical.
One concern about cluster sampling is periodicity.
The Kruskal-Wallis test is a nonparametric procedure that allows us to determine if a
difference exists among the medians of three or more populations.
With the continuous uniform probability distribution, the probability of any interval in
the distribution is equal to any other interval with the same width.
If the hypothesis test is used in a quality control setting, the alternative hypothesis takes
the stance that the process is not behaving as it should and needs some sort of attention.
The Wilcoxon rank-sum test requires that the populations from which the samples are
drawn follow the normal probability distribution.
The mathematical expression that describes the shape of the curve for the exponential
distribution is known as the exponential probability density function.
Parametric statistics require the level of data measurement to be ordinal or interval.
With one-way ANOVA, we will have a greater chance of rejecting the null hypothesis
when more variation in the data is due to the SSB rather than the SSW.
When displaying the trend projection graphically, the time period is placed on the y-axis
and the forecasted value is placed on the x-axis.
The test statistic for the two-tail sign test is the larger number of the plus signs versus
the minus signs.
The purpose of calculating a centered moving average is to remove the seasonal
component from the time series.
The degrees of freedom for the critical value for a hypothesis test for a single
population variance is n – 2.
The p-value for the hypothesis test for the overall regression model represents the
probability of obtaining an F-test statistic at least as extreme as the one observed from
the sample if the alternative hypothesis were indeed true.
Determining the proportion of customers who have credit scores greater than 700 is an
example of descriptive statistics.
When testing the significance of the regression coefficient, the null hypothesis assumes
that no relationship exists between the dependent and independent variables.
A 95% confidence interval will always be wider than a 95% prediction interval using
the same value of x.
The mode is the most useful measure of central tendency for a data set.
The only limitation in the number of continuous values within an interval is the level of
precision of the measuring instrument.
Discrete random variables have outcomes that take on any numerical value as a result
of conducting an experiment.
The mean of a discrete probability distribution is the weighted average of the outcomes
of the random variables that comprise it.
Costco Wholesale claims that Costco members prefer its Kirkland brand toilet paper
over the leading national brand. To test this claim, Costco recorded the preferences of a
random sample of customers which are summarized in the table below.
The sample size, n, for this hypothesis test is ________.
A) 20
B) 38
C) 58
D) 63
The following data represents the actual talk time, in hours, for the Samsung
smartphone for 11 users.
The 60th percentile of this data set is ________.
A) 21.6
B) 21.9
C) 23.3
D) 24.6
AutoTrader.com would like to test if a difference exists in the age of three different
types of vehicles currently on the road–trucks, cars, and vans. The following data
represent the age of a random sample of trucks, cars, and vans.
The sum of squares between for these observations is ________.
A) 28.7
B) 32.0
C) 39.8
D) 44.2
A ________ component is present in a time series if a consistent pattern in the data can
be associated with a calendar.
A) cyclical
B) seasonal
C) random
D) trend
AutoTrader.com would like to test if a difference exists in the age of three different
types of vehicles currently on the road–trucks, cars, and vans. The following data
represent the age of a random sample of trucks, cars, and vans.
The conclusion(s) for the Tukey-Kramer multiple comparisons test using α = 0.05 is/are
that the average age of _____________________________________.
A) trucks is different from the average age of vans
B) trucks is different from the average age of cars
C) cars is different from the average age of vans
D) cars is different from the average age of vans. Also, the average age of trucks is
different than the average age of cars
Entertainment Software Association would like to test if the average age of “gamers”
(those that routinely play video games) is more than 30 years old. A Type I error would
occur if Entertainment Software Association concludes that the average age of gamers
is
_________________________.
A) 30 years or less when, in reality, the average age is more than 30 years
B) greater than 30 years when, in reality, the average age is 30 years or less
C) not equal to 30 years when, in reality, the average age is equal to 30 years
D) equal to 30 years when, in reality, the average age is not equal to 30 years
John Charleston owns a heating oil delivery company that services 1,540 residences.
John would like to estimate the number of customers that have oil storage tanks that are
less than 100 gallons in capacity. A random sample of 200 customers found that 63 had
an oil tank that was less than 100 gallons. The 80% confidence interval to estimate the
proportion of customers with oil tanks less than 100 gallons is ________.
A) (0.276, 0.354)
B) (0.183, 0.447)
C) (0.216, 0.414)
D) (0.151, 0.480)
Entertainment Software Association would like to test if the standard deviation for the
age of “gamers” (those that routinely play video games) is equal to 6.0 years. The
standard deviation for the age from a random sample of 24 gamers is 3.8 years. Using α
= 0.05, the conclusion for this hypothesis test would be that because the test statistic is
__________________________.
A) less than the lower critical value, we reject the null hypothesis and conclude that the
standard deviation for the age of gamers is not equal to 6.0 years
B) between the lower and upper critical values, we reject the null hypothesis and cannot
conclude that the standard deviation for the age of gamers is not equal to 6.0 years
C) more than the upper critical value, we fail to reject the null hypothesis and cannot
conclude that the standard deviation for the age of gamers is not equal to 6.0 years
D) between the lower and upper critical values, we fail to reject the null hypothesis and
cannot conclude that the standard deviation for the age of gamers is not equal to 6.0
years
Assume that the number of pieces of junk mail per day that a person receives in their
mail box follows the Poisson distribution and averages 4.3 pieces per day. What is the
probability that this person will receive one or two pieces of junk mail tomorrow?
A) 0.1065
B) 0.1227
C) 0.1838
D) 0.2369
Two events are considered to be ________ if they cannot occur at the same time during
the experiment.
A) mutually exclusive
B) collectively exhaustive
C) independent
D) dependent
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 p-value for this hypothesis test
would be between ________.
A) 0.01 and 0.025
B) 0.025 and 0.05
C) 0.05 and 0.10
D) 0.10 and 0.20
According to Bureau of Labor Statistics, 26.0% of the total part-time workforce in the
U.S. was between the ages of 25 and 34 during a recent month. A random sample of 90
part-time employees was selected during this month. Using the normal approximation
to the binomial distribution, what is the probability that exactly 23 people from this
sample were between the ages of 25 and 34?
A) 0.0419
B) 0.0951
C) 0.1615
D) 0.2394
Consider the following data set:
Variable 1:
Variable 2:
The sample covariance for this data set is
A) “2.55
B) “1.19
C) 3.87
D) 13.0
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 (X1), the employee’s weekly base salary before commissions (X2), 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 regression model was chosen using a data set of employee statistics:
The first employee from the data set had the following values:
Sales = 11
Experience = 3 years
Salary = $498
Education = Bachelor’s degree
The residual for this employee is ________.
A) 0.9
B) 5.0
C) -1.7
D) -3.6
A statistics class at Wilmington College has 25 students of which 15 are math majors
and 10 are business majors. The professor randomly selects five students to work
together on a group project. What is the probability that none of the students in this
group are business majors?
A) 0.0230
B) 0.0565
C) 0.1007
D) 0.1436
The time that customers wait to be served at the delicatessen for a grocery store follows
the uniform distribution between 0 and 7 minutes. What is the probability that a
randomly selected customer will wait between 1 and 5 minutes at the deli?
A) 0.1429
B) 0.2857
C) 0.4286
D) 0.5714
According to Pew Research Center, 71% of Internet users accessed video-sharing sites
last month. A random sample of 50 Internet users was selected. Using the normal
approximation to the binomial distribution, what is the probability that 37 or more
people from this sample access video-sharing sites?
A) 0.1492
B) 0.2676
C) 0.3783
D) 0.4602
The following chart shows the average movie ticket price according to a survey by the
National Association of Theater Owners.
This chart is an example of a _________ chart.
A) horizontal bar
B) vertical bar
C) stacked bar
D) Pareto
A professor would like to test the hypothesis that the average number of minutes that a
student needs to complete a statistics exam has a standard deviation that is less than 5.0
minutes. A random sample of 15 students was selected and the sample standard
deviation for the time needed to complete the exam was found to be 4.0 minutes. The
test statistic for this hypothesis test would be ________.
A) 8.96
B) 10.42
C) 13.61
D) 17.67
The Dean of the Business School at City University would like to test the hypothesis
that a difference exists between the median 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 grade for each course
is shown below.
The critical value for this hypothesis test using α = 0.10 is ________.
A) 4
B) 6
C) 8
D) 9
Nintendo Sony would like to test the hypothesis that a difference exists in the average
age of users of a Wii, a PlayStation, or an Xbox console game. The following data
represent the age of a random sample of Wii, PlayStation, and Xbox users.
The sum of squares within for these observations is ________.
A) 262.9
B) 376.0
C) 509.1
D) 575.0
The following data represents the amount of money that individuals spent on gifts for
Mother’s Day.
$110 $132 $144 $168 $141 $100 $184 $137 $134 $148 $128 $166
Determine the five-number summary for this data.
Analyzing snowfall amounts in New York over the past 100 years to help predict future
weather patterns is an example of using primary data.
A large statistics class meets on Monday, Wednesday, and Friday each week during the
semester. The following data shows the number of absent students for the last nine
classes.
The following dummy variables were created:
The regression results are shown in the table below.
The forecast for the number of absent students for Class 10 using this model is
________.
A) 3.7
B) 4.3
C) 5.8
D) 7.3
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.
The multiple coefficient of determination for this model is ________.
A) 0.6644
B) 0.7796
C) 0.8163
D) 0.9035
Steve’s average golf score at his local course is 93.6 from a random sample of 34 rounds
of golf. Assume that the population standard deviation for his golf score is 4.2. The 90%
confidence interval around this sample mean is ________.
A) (89.0, 98.3)
B) (90.5, 96.7)
C) (93.2, 94.0)
D) (92.4, 94.8)
The following data represent the square footage of 10 three-bedroom condos for sale in
Hilton Head, South Carolina.
1,559 1,625 1,167 1,264 1,676 1,300 2,058 1,126 1,858 1,321
Determine the interquartile range for this sample. Are there any outliers in this data set?
The airline industry defines no-shows as passengers who have purchased a ticket but
fail to arrive at the gate on time for departure. Southwest Airlines operates many flights
from Philadelphia to Dallas and experienced the following no-show probability
distribution last year.
The following data represent the number of no-shows that occurred on a random sample
of 120 flights between these two cities this year.
Southwest Airlines would like to know if the probability distribution of no-shows has
changed between last year and this year on flights between these two cities using α =
0.05. The test statistic for this sample is ________.
A) 7.44
B) 13.58
C) 16.94
D) 19.21
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 less than 1,800 hours?
A) 0.3567
B) 0.4056
C) 0.5934
D) 0.7774
The following distribution shows the frequency distribution of the number of shots a
particular NBA player blocked in one game for a random sample of 100 games.
You have been assigned the task to test if the distribution of blocked shots per game for
this player follows the Poisson distribution using α = 0.05. The degrees of freedom for
the critical value is ________.
A) 4
B) 5
C) 6
D) 7
A ________ component is present in a time series if a general upward or downward
movement can be observed in the data.
A) cyclical
B) seasonal
C) random
D) trend
Dr. Chris is a chiropractor and treats patients from her home office. The following data
represent the number of patients that Dr. Chris treated over the past six days.
Calculate the patient forecast for Day 7 using exponential smoothing with trend
adjustment with α = 0.7 and β = 0.8.
A local Chamber of Commerce would like to test the hypothesis that there is a
difference in the standard deviation for the monthly rent for a one-bedroom apartment
in York when compared to a one-bedroom apartment in Lancaster. The following data
summarizes the sample statistics for one-bedroom apartment rents in both locations.
Test the hypothesis using α = 0.05.
According to a report by Capital Economics, the average monthly mortgage payment in
Chicago is $1,002. Assume that the standard deviation for monthly mortgage payments
in Chicago is $168. To confirm these results, a random sample of 55 homeowners in
Chicago was selected and found to have an average monthly mortgage payment of
$1,030. Do the results of this survey support the report by Capital Economics?
Hallmark would like to test the hypothesis that those celebrating Valentine’s Day will
spend more than an average of $125 on gifts. A random sample of 18 people celebrating
Valentine’s Day spent an average of $148.50 with a standard deviation of $34.90.
Hallmark would like to set α = 0.01. Use the critical value approach to test this
hypothesis.
AT&T would like to test the hypothesis that the average revenue per retail user for
Verizon Wireless customers equals $50. A random sample of 32 Verizon Wireless
customers provided an average revenue of $54.70. It is believed that the population
standard deviation for the revenue per retail user is $11.00. AT&T would like to set α =
0.05. Use the p-value approach to test this hypothesis.
Dave is a photographer who sells his prints at Jersey Art during the summer months on
consignment. Dave sells three different size prints during the months of June, July, and
August. The following contingency table shows the number of prints sold each month
last summer..
Perform a hypothesis test to determine if the print size and the month that it was sold
are independent variables using α = 0.01.
John is the manager at the Deerfield Golf Course and would like to test the hypothesis
that there is more variability in golf scores at the Pike Creek Golf Course, which is a
competitor in the area, when compared to golf scores at his course. The following data
summarizes the sample statistics for golf scores from both courses.
Test the hypothesis using α = 0.10.
A random sample of 20 cars was selected. The following table shows the number of
cars grouped by age in years.
What is the approximate average age of cars from this sample?
Avalon Bagel provides take-out service for a variety of breakfast items. The following
table shows the number of orders that have been recently placed grouped by the size of
the order in dollars.
What is the approximate average order size for this sample?