If the null hypothesis states that there is no difference between the mean net income of
retail stores in Chicago and New York City, then the test is two-tailed.
To determine the size of a sample, the standard deviation of the population must be
estimated by either taking a pilot survey or by approximating it based on knowledge of
the population.
The principal difference between the interval and ratio scale is that the ratio scale has a
meaningful zero point.
The sign test is an appropriate nonparametric test for dependent samples.
What is the purpose of transformations in regression analysis?
When the standard deviations are equal but unknown, a test for the differences between
two population means has n – 1 degrees of freedom.
A listing of 100 family annual incomes is an example of statistics.
How is the significance level related to the probability of a Type I error?
A p-value is the same as a stated significance level.
A way to decide which common stock to purchase is to determine the profit that might
be lost because the exact state of nature (the market behavior) was not known at the
time the investor bought the stock. This potential loss is called opportunity loss or
regret.
Control charts can be developed for both variables and attributes.
In cluster sampling, a population is divided into subgroups called clusters and a sample
is randomly selected from each cluster.
An ordinal level of measurement implies some sort of ranking.
The Wilcoxon rank-sum test compares two dependent populations.
One assumption underlying linear regression is that the X values are normally
distributed.
A sample of 2,000 union members was selected, and a survey recorded their opinions
regarding a proposed management union contract. A total of 1,600 members were in
favor of it. A 95% confidence interval estimated that the population proportion was
between 0.78 and 0.82. This indicates that about 80 out of 100 similarly constructed
intervals would include the population proportion.
For a one-tailed hypothesis test, the critical z value of the test statistic is -2.33. Which of
the following is TRUE about the hypothesis test?
A. α = 0.05 for a lower-tailed test
B. α = 0.01 for a lower-tailed test
C. α = 0.05 for an upper-tailed test
D. α = 0.01 for an upper-tailed test
A Type II error is the probability of rejecting the null hypothesis when it is actually
In multiple regression analysis, an F-statistic is used to test the global hypothesis, H0:
.
To construct a pie chart, relative class frequencies are used to graph the ‘slices” of the
pie.
To apply a Poisson probability distribution, the mean can be computed as __________.
A. nπ
B.
C. e-x
D.
Random samples of four items are selected from a manufacturing process at regular
intervals and a certain quality characteristic is measured. After 25 samples, ΣX =
15,350 and ΣR = 411.4. To construct a mean chart, what is the lower control limit
(LCL) for the mean?
A. 602.004
B. 411.400
C. 625.666
D. 0.00
The manager of Paul’s fruit and vegetable store is considering the purchase of a new
seedless watermelon from a wholesale distributor. Since this seedless watermelon costs
$4, will sell for $7, and is highly perishable, he only expects to sell between six and
nine of them. What is the payoff value for the purchase of eight watermelons when the
demand is for six watermelons?
A. 17
B. 21
C. 24
D. 10
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?
This example is what type of test?
A. A one-sample test of means.
B. A two-sample test of means.
C. A paired t-test.
D. A test of proportions.
When applying the special rule of addition for mutually exclusive events, the joint
probability is _______.
A. 1
B. .5
C. 0
D. Unknown
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. [0.6591, 0.7045]
C. [0.6659, 0.6941]
D. [0.6795, 0.6805]
The average cost of tuition plus room and board at a small private liberal arts college is
reported to be $8,500 per term, but a financial administrator believes that the average
cost is higher. A study conducted using 350 small liberal arts colleges showed that the
average cost per term is $8,745. The population standard deviation is $1,200. Let α =
0.05. What is the critical z value for this test?
A. +1.960
B. -1.960
C. +1.645
D. -1.645
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 is the critical value of F at the 0.05 level of significance?
A. 5.85
B. 5.35
C. 3.18
D. 4.03
What is the interpretation of a 96% confidence level?
A. There’s a 96% chance that the given interval includes the TRUE value of the
population parameter.
B. Approximately 96 out of 100 such intervals would include the TRUE value of the
population parameter.
C. There’s a 4% chance that the given interval does not include the TRUE value of the
population parameter.
D. The interval contains 96% of all sample means.
Each salesperson in a large department store chain is rated on their sales ability and
their potential for advancement. The data for the 500 sampled salespeople are
summarized in the following table.
What is the probability that a salesperson selected at random will have an excellent
potential for advancement given they also have average sales ability?
A. 0.27
B. 0.30
C. 0.404
D. 0.45
A company is researching the effectiveness of a new website design to decrease the
time to access a website. Five website users were randomly selected, and their times (in
seconds) to access the website with the old and new designs were recorded. To compare
the times, they computed (new website design time – old website design time). The
results follow.
What is the null hypothesis?
A. H0: d = 0
B. H0: d ≠0
C. H0: d ≤ 0
D. H0: d ≥ 0
What type of variation can be reduced, or even eliminated, and is usually nonrandom in
nature?
A. chance
B. external
C. assignable
D. co-variation
A study of interior designers’ opinions with respect to the most desirable primary color
for executive offices showed the following:
What is the probability that a designer does not prefer yellow?
A. 0.000
B. 0.765
C. 0.885
D. 1.000
A student wanted to construct a 95% confidence interval for the mean age of students in
her statistics class. She randomly selected nine students. Their average age was 19.1
years with a sample standard deviation of 1.5 years. What is the best point estimate for
the population mean?
A. 2.1 years
B. 1.5 years
C. 19.1 years
D. 9 years
A group of statistics students decided to conduct a survey at their university to estimate
the average (mean) amount of time students spent studying per week. They sampled
554 students and found a mean of 22.3 hours per week. Assuming a population standard
deviation of six hours, what is the 95% level of confidence?
A. [21.80, 22.80]
B. [16.3, 28.3]
C. [21.64, 22.96]
D. [20.22, 22.0]
The Office of Student Services at a large western state university maintains information
on the study habits of its full-time students. Their studies indicate that the mean amount
of time undergraduate students study per week is 20 hours. The hours studied follows
the normal distribution with a standard deviation of six hours. Suppose we select a
random sample of 144 current students. What is the standard error of the mean?
A. 0.50
B. 6.00
C. 0.25
D. 2.00
The average starting salary of individuals with a master’s degree in statistics is normally
distributed with a mean of $48,000 and a standard deviation of $6,000. What is the
probability that a randomly selected individual with a master’s in statistics will get a
starting salary of at least $55,500?
A. 0.121
B. 0.891
C. 0.379
D. 0.098
A company is researching the effectiveness of a new website design to decrease the
time to access a website. Five website users were randomly selected and their times (in
seconds) to access the website with the old and new designs were recorded. The results
follow.
What is the value of the test statistic to test for differences in the times?
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 Y-intercept of the linear equation?
If a hypothesis states that one population mean is greater than another population mean,
then the test is _______________.
The American Auto Association reports that the mean price per gallon of regular
gasoline is $3.10, with a population standard deviation of $0.20. Assume a random
sample of 16 gasoline stations is selected and their mean cost for regular gasoline is
computed. What is the probability that the sample mean is between $2.98 and $3.12?
In relative terms, a _______ confidence level leads to a narrower confidence interval.
Airlines monitor the causes of flights arriving late. A total of 75% of flights are late
because of weather, while 35% of flights are late because of ground operations. A full
15% of flights are late because of weather and ground operations. What is the
probability that a flight arrives late because of weather or ground operations?
In a weighted index, the __________ variable is usually the weight.
The following data was collected comparing car prices and quantity sold (thousands).
Compute the Paasche price index to compare car prices in 2010 to 2000.
A scale used to measure a quantitative variable is either _______________ or
______________.
For the following data, are any of the observations an outlier?