The annual income for a sample of 500 part-time students is normally distributed with a
mean income of $30,000 and a standard deviation of $3,000. The income range that
separates the top 25% from the lower 75% is __________.
When all the items in a population have an equal chance of being selected for a sample,
the process is called _________________.
A. Simple random sampling
B. z-score
C. Sampling error
D. Nonprobability sampling
What does the coefficient of determination equal if r = 0.89?
A. 0.9412
B. 0.0121
C. 0.7921
D. 0.1100
If Gallup, Harris, and other pollsters asked people to indicate their political party
affiliation as Democrat, Republican, or Independent, the data gathered would be an
example of which scale of measurement?
A. Nominal
B. Ordinal
C. Interval
D. Ratio
In regression analysis, what is the predictor variable called?
A. Independent variable
B. Dependent variable
C. Correlation variable
D. Variable of determination
Over the last six months, the following numbers of absences have been reported: 6, 0,
10, 14, 8, and 0. What is the median number of monthly absences?
A. 6
B. 7
C. 8
D. 3
The weights of a sample of crates ready for shipment to Moscow, Russia are (in
kilograms): 103, 97, 101, 106, and 103. What is the mean deviation?
A. 0 kg
B. 6.9 kg
C. 102.0 kg
D. 2.4 kg
A research firm wants to compute an interval estimate with 90% confidence for the
mean time to complete an employment test. Assuming a population standard deviation
of three hours, what is the required sample size if the error should be less than a half
hour?
A. 196
B. 98
C. 10
D. 16
What type of variable is “pounds of popcorn” served at a movie theater?
A. Interval
B. Ratio
C. Discrete
D. Continuous
Refer to the following breakdown of responses to a survey of “Are you concerned about
being tracked while connected to the Internet?”
What type of chart should be used to show relative class frequencies?
A. A pie chart
B. A bar chart
C. A histogram
D. A frequency polygon
A random sample of 400 families who planned to buy a vacation residence revealed that
228 families want to buy a condominium in Florida. At the 0.01 significance level, test
the statement that 55% of those families who plan to purchase a vacation residence in
Florida want a condominium. To decide if the sample data support the 55%, state your
decision in terms of the null hypothesis. Use a 0.01 level of significance.
A sample of the paramedical fees charged by clinics revealed these amounts: $55, $49,
$50, $45, $52, and $55. What is the median charge?
A. $47.50
B. $51.00
C. $52.00
D. $55.00
A sales manager for an advertising agency believes that there is a relationship between
the number of contacts that a salesperson makes and the amount of sales dollars earned.
A regression analysis shows the following results:
What is the slope of the linear equation?
A. -12.201
B. 2.195
C. -1.860
D. 12.505
A recent study focused on the number of times men and women send a Twitter message
in a day. The information is summarized next.
At the .01 significance level, is there a difference in the mean number of times men and
women send a Twitter message in a day? What is the value of the test statistic for this
hypothesis test?
A. 2.668
B. 2.672
C. 2.58
D. 2.40
Accounting procedures allow a business to evaluate its inventory costs based on two
methods: LIFO (Last In First Out) or FIFO (First In First Out). A manufacturer
evaluated its finished goods inventory (in $000s) for five products with the LIFO and
FIFO methods. To analyze the difference, they computed (FIFO – LIFO) for each
product. Based on the following results, does the LIFO method result in a lower cost of
inventory than the FIFO method?
What is the decision at the 5% level of significance?
A. Fail to reject the null hypothesis and conclude LIFO is more effective.
B. Reject the null hypothesis and conclude LIFO is more effective.
C. Reject the alternate hypothesis and conclude LIFO is more effective.
D. Fail to reject the null hypothesis.
The Intelligence Quotient (IQ) test scores for adults are normally distributed with a
mean of 100 and a standard deviation of 15. What is the probability we could select a
sample of 50 adults and find the mean of this sample is between 95 and 105?
A. 0.0182
B. 0.9818
C. 1.00
D. Very unlikely
An automatic machine inserts mixed vegetables into a plastic bag. Past experience
revealed that some packages were underweight and some were overweight, but most of
them had satisfactory weight.
What is the probability of selecting three packages that are satisfactory?
A. 0.900
B. 0.810
C. 0.729
D. 0.075
Twenty-one executives in a large corporation were randomly selected to study the effect
of several factors on annual salary (expressed in $000s). The factors selected were age,
seniority, years of college, number of company divisions they had been exposed, to and
the level of their responsibility. The results of the regression analysis follow:
Which one of the following is the dependent variable?
A. Age
B. Seniority
C. Level of responsibility
D. Annual salary
Based on the Nielsen ratings, the local CBS affiliate claims its 11 p.m. newscast reaches
41% of the viewing audience in the area. In a survey of 100 viewers, 36% indicated that
they watch the late evening news on this local CBS station. What is your decision if α =
0.01?
A. Fail to reject the null hypothesis.
B. Reject the null hypothesis and conclude the newscast does not reach 41% of the
audience.
C. Fail to reject the alternate and conclude the newscast does not reach 41% of the
audience.
D. Reject the alternate and conclude the newscast reaches about 41% of the audience.
An automatic machine inserts mixed vegetables into a plastic bag. Past experience
revealed that some packages were underweight and some were overweight, but most of
them had satisfactory weight.
What is the probability of selecting three packages that are overweight?
A. 0.0000156
B. 0.0004219
C. 0.0000001
D. 0.075
Using the following statistics to describe a distribution of data, what is the interquartile
range?
Minimum = 10
Q1 = 25
Median = 50
Q3 = 75
Maximum = 95
A. 85
B. 50
C. 15
D. 20
A total of 60% of the customers of a fast food chain order a hamburger, French fries,
and a drink. If a random sample of 15 cash register receipts is selected, what is the
probability that 10 or more will show that the above three food items were ordered?
A. 1.000
B. 0.186
C. 0.403
D. 0.000
A survey of an urban university (population of 25,450) showed that 750 of 1,100
students sampled attended a home football game during the season. Using the 90%
level of confidence, what is the confidence interval for the proportion of students
attending a football game?
A. [0.7510, 0.8290]
B. [0.6569, 0.7031]
C. [0.6659, 0.6941]
D. [0.6795, 0.6805]
It has been hypothesized that overall academic success for college freshmen as
measured by grade point average (GPA) is a function of IQ scores, X1, hours spent
studying each week, X2, and one’s high school average, X3. Suppose the regression
equation is . The multiple standard error is
6.313 and R2 = 0.826.
Which independent variable has the greatest effect on GPA?
The tread life of tires mounted on light-duty trucks follows the normal probability
distribution with a mean of 60,000 miles and a standard deviation of 4,000 miles.
Suppose you bought a set of four tires, what is the likelihood the mean tire life of these
four tires is between 57,000 and 63,000 miles?
A. 0.4332
B. 0.8664
C. 1.00
D. Very likely
What are the degrees of freedom for a contingency table analysis?
A. n – 1
B. Rows – Columns
C. (Rows) (Columns)
D. (Rows – 1) (Columns – 1)
In the equation, Ŷ = a + bX, what is Ŷ?
A. It is the slope of the line.
B. It is the Y intercept.
C. It is the predicted value of Y, given a specific X value.
D. It is the value of Y when X = 0.
Refer to the following breakdown of responses to a survey of “Are you concerned about
being tracked while connected to the Internet?”
What is the class with the greatest frequency?
A. Very concerned
B. Somewhat concerned
C. No concern
D. None Apply
The mean, as a measure of central location, would be inappropriate for which one of the
following?
A. Ages of adults at a senior citizen center
B. Incomes of lawyers
C. Number of pages in textbooks on statistics
D. Marital status of college students at a particular university
Recently, students in a marketing research class were interested in the driving behavior
of students. Specifically, the marketing students were interested in finding out if
exceeding the speed limit was related to social activity. They collected the following
responses from 100 randomly selected students:
Using 0.05 as the significance level, what is the critical value for the test statistic?
A. 9.488
B. 5.991
C. 7.815
D. 3.841
What are the critical z-values for a two-tailed hypothesis test if α = 0.01?
A. 1.960
B. 2.326
C. 2.576
D. 1.645
When testing the safety of cars using crash tests, a sample of one or two cars is used
because ___________.
A. Sampling is more accurate
B. Cars are destroyed
C. It is quicker
D. The population is very large
Refer to the following breakdown of responses to a survey of “Are you concerned about
being tracked while connected to the Internet?”
What percent of the responses indicated that users were somewhat concerned?
A. 40%
B. 70%
C. 20%
D. 100%
Two accounting professors decided to compare the variance of their grading procedures.
To accomplish this, they each graded the same 10 exams, with the following results:
What are the degrees of freedom for the denominator of the F ratio?
A. 20
B. 18
C. 10
D. 9
Elly’s Hotdog Emporium is famous for its chilidogs. Elly’s latest sales indicate that 30%
of the customers order their chilidogs with hot peppers. Suppose 15 customers are
selected at random. What is the probability that all 15 will want hot peppers?
The branch of statistics that uses sample information to make conclusions about a
population is called _________________ statistics.
Two business major students, in different sections of an economics class, were
comparing test scores. The following shows the sections’ mean and standard deviation.
The student in section 1 scored 84. The student’s z score would be _________.
A __________ shows the interquartile range.
In a multiple regression analysis, the following correlation matrix was computed.
What does the correlation matrix suggest about the independent variables?
A company wants to study the effect of an employee’s length of employment on their
number of workdays absent. The results of the regression analysis follow.
What is the meaning of a negative slope?
All values in an F distribution must be _____________.
Six people have declared their intentions to run for a seat on the school board in the
next local election. A poll is conducted during the campaign among 1,020 randomly
sampled voters to determine if there is any clear preference among the voters. The
responses are shown next.
What is the critical value at the 1% level of significance?
Correlation among successive observations of the dependent variable is called
________________.
A small manufacturing company with 52 employees has annual salaries distributed such
that the mean is $25,459, the median is $24,798 and the mode is $24,000. An additional
foreman is hired at an annual salary of $50,700. The measure of central location that is
affected by the addition of this salary is called the _________________.
We are interested in knowing if the following frequency distribution is normally
distributed. The population mean and standard deviation of the data are 600 and 160,
respectively.
To test the hypothesis that the frequency distribution is normally distributed, the value
of the chi-square test statistic is 12.19. What is the decision regarding the null
hypothesis tested at the .05 level of significance?
The following frequency distribution shows the distribution of delivery times (in days)
for swimstuff.com customer orders during the last month.
What is the relative frequency for orders delivered in three days or more?
The research director of a large oil company studied the buying habits of consumers
with respect to the amount of gasoline purchased at full-service pumps. The sample
mean amount is 11.5 gallons and the median amount is 11.95 gallons. The standard
deviation of the sample is 4.5 gallons. What is Pearson’s coefficient of skewness here?
When testing for a difference between the means of two dependent samples, the sample
test statistic is a ______________.
The measure of central location that requires the data to be ranked before it is possible
to determine it is called the _________.
A collection of one or more possible outcomes of an experiment is called a(n)
___________.
The waiting time for patients at a local walk-in health clinic follows a normal
distribution with a mean of 15 minutes and a population standard deviation of 5
minutes. The clinic wants to know if the waiting time is less than 15 minutes. The
quality-assurance department sampled 50 patients and found that the mean waiting time
was 14.25 minutes. For a significance level of 0.05, what is the critical value?