True or False: The brand of TV one owns is an example of a numerical variable.
True or False: TABLE 17-10
Given below are results from the regression analysis where the dependent variable is
the number of weeks a worker is unemployed due to a layoff (Unemploy) and the
independent variables are the age of the worker (Age), the number of years of education
received (Edu), the number of years at the previous job (Job Yr), a dummy variable for
marital status (Married: 1 = married, 0 = otherwise), a dummy variable for head of
household (Head: 1 = yes, 0 = no) and a dummy variable for management position
(Manager: 1 = yes, 0 = no). We shall call this Model 1. The coefficient of partial
determination ( ) of each of the 6 predictors are, respectively,
0.2807, 0.0386, 0.0317, 0.0141, 0.0958, and 0.1201.
Model 2 is the regression analysis where the dependent variable is Unemploy and the
independent variables are Age and Manager. The results of the regression analysis are
given below:
Referring to Table 17-10, Model 1, the null hypothesis H0 : β1 = β2= β3 = β4 = β5 = β6
= 0 implies that the number of weeks a worker is unemployed due to a layoff is not
related to one of the explanatory variables.
TABLE 11-4
An agronomist wants to compare the crop yield of 3 varieties of chickpea seeds. She
plants 15 fields, 5 with each variety. She then measures the crop yield in bushels per
acre. Treating this as a completely randomized design, the results are presented in the
table that follows.
True or False: Referring to Table 11-4, the test is valid only if the population of crop
yields has the same variance for the 3 varieties.
True or False: The t distribution is used to develop a confidence interval estimate of the
population proportion when the population standard deviation is unknown.
TABLE 8-17
A random sample of 100 stores from a large chain of 500 garden supply stores was
selected to determine the mean number of lawnmowers sold at an end-of-season
clearance sale. The sample results indicated a mean of 6 and a standard deviation of 2
lawnmowers sold. A 95% confidence interval (5.623 to 6.377) was established based on
these results.
True or False: Referring to Table 8-17, the confidence interval estimate of the mean
with finite population correction will be wider in range than confidence interval
estimate without finite population correction.
TABLE 12-6
According to an article in Marketing News, fewer checks are being written at the
grocery store checkout than in the past. To determine whether there is a difference in
the proportion of shoppers who pay by check among three consecutive years at a 0.05
level of significance, the results of a survey of 500 shoppers in three consecutive years
are obtained and presented below.
True or False: Referring to Table 12-6, the null hypothesis cannot be rejected.
True or False: The only reliable way a researcher can make statistical inferences from a
sample to a population is to use nonprobability sampling methods.
True or False: Referring to Table 14-17, there is suffcient evidence
that at least one of the explanatory variables is related to the number
of weeks a worker is unemployed due to a layo# at a 10% level of
signi&cance.
TABLE 14-17
Given below are results from the regression analysis where the
dependent variable is the number of weeks a worker is unemployed
due to a layo# (Unemploy) and the independent variables are the age
of the worker (Age) and a dummy variable for management position
(Manager: 1 = yes, 0 = no).
The results of the regression analysis are given below:
True or False: When an additional explanatory variable is introduced into a multiple
regression model, the adjusted r2 can never decrease.
True or False: Changes in the system to reduce common cause variation are the
responsibility of management.
At Eastern University, 60% of the students are from suburban areas, 30% are from rural
areas, and 10% are from urban areas. Of the students from the suburban areas, 60% are
nonbusiness majors. Of the students from the rural areas, 70% are nonbusiness majors.
Of the students from the urban areas, 90% are nonbusiness majors. If a randomly
selected student is not a business major, the probability that the student is from the
urban area is
A) 0.136.
B) 0.214.
C) 0.666.
D) 0.706.
If, as a result of a hypothesis test, you reject the null hypothesis when it is false, then
you have committed
A) a Type II error.
B) a Type I error.
C) no error.
D) an acceptance error.
TABLE 18-1
A local newspaper has 10 delivery boys who each deliver the morning paper to 50
customers every day. The owner decides to record the number of papers delivered on
time for a 10-day period for one of the delivery boys and construct a p chart to see
whether the percentage is too erratic.
Referring to Table 18-1, which expression best characterizes the p chart?
A) Cycles
B) Increasing trend
C) In-control
D) Individual outliers
The t distribution
A) assumes the population is normally distributed.
B) approaches the normal distribution as the sample size increases.
C) has more area in the tails than does the normal distribution.
D) All of the above.
A ________ is a numerical quantity computed from the data of a sample and is used in
reaching a decision on whether or not to reject the null hypothesis.
A) significance level
B) critical value
C) test statistic
D) parameter
TABLE 11-4
An agronomist wants to compare the crop yield of 3 varieties of chickpea seeds. She
plants 15 fields, 5 with each variety. She then measures the crop yield in bushels per
acre. Treating this as a completely randomized design, the results are presented in the
table that follows.
Referring to Table 11-4, construct the ANOVA table from the sample data.
TABLE 19-2
The following payoff matrix is given in dollars.
Suppose the probability of Event 1 is 0.5 and Event 2 is 0.5.
Referring to Table 19-2, the coefficient of variation for Action A is
A) 12.8%.
B) 33.3%.
C) 133.33%.
D) 333.3%.
Suppose that past history shows that 60% of college students prefer Brand C cola. A
sample of 5 students is to be selected. The probability that exactly 1 prefers brand C is
________.
TABLE 12-9
Many companies use well-known celebrities as spokespersons in their TV
advertisements. A study was conducted to determine whether brand awareness of
female TV viewers and the gender of the spokesperson are independent. Each in a
sample of 300 female TV viewers was asked to identify a product advertised by a
celebrity spokesperson. The gender of the spokesperson and whether or not the viewer
could identify the product was recorded. The numbers in each category are given below.
Referring to Table 12-9, the calculated test statistic is
A) -0.1006.
B) 0.00.
C) 5.9418.
D) 6.1194.
Which of the following is an assumption required by the Analysis of Means (ANOM)?
A) The variance of the groups is different.
B) The observations from each of the groups are assumed to be approximately normally
distributed.
C) The shape of the distribution of the observations from the groups is different.
D) The number of observations in each group has to be at least 30.
How many tissues should the Kimberly Clark Corporation package of Kleenex contain?
Researchers determined that 60 tissues is the mean number of tissues used during a
cold. Suppose a random sample of 100 Kleenex users yielded the following data on the
number of tissues used during a cold: = 52,
S = 22. Give the null and alternative hypotheses to determine if the number of tissues
used during a cold is less than 60.
A) H0 : 60 and H1 : > 60.
B) H0 : 60 and H1 : < 60.
C) H0 : 60 and H1 : ≠52.
D) H0 : = 52 and H1 : ≠52.
TABLE 1-1
The manager of the customer service division of a major consumer electronics company
is interested in determining whether the customers who have purchased a Blu-ray
player made by the company over the past 12 months are satisfied with their products.
Referring to Table 1-1, the possible responses to the question “Out of a 100 point score
with 100 being the highest and 0 being the lowest, what is your satisfaction level with
the Blu-ray player that you purchased?” result in
A) a nominal scale variable.
B) an ordinal scale variable.
C) an interval scale variable.
D) a ratio scale variable.
If either event A or event B must occur, then events A and B are said to be
A) mutually exclusive.
B) independent.
C) collectively exhaustive.
D) None of the above.
A national trend predicts that women will account for half of all business travelers in
the next 3 years. To attract these women business travelers, hotels are providing more
amenities that women particularly like. A recent survey of American hotels found that
70% offer hairdryers in the bathrooms. Consider a random and independent sample of
20 hotels. Find the probability that more than 7, but less than 13, of the hotels in the
sample offered hairdryers in the bathrooms.
Referring to Table 14-19, what is the p-value of the test statistic when
testing whether LawnSize makes a signi&cant contribution to the
model in the presence of Income?
TABLE 14-19
The marketing manager for a nationally franchised lawn service
company would like to study the characteristics that differentiate
home owners who do and do not have a lawn service. A random
sample of 30 home owners located in a suburban area near a large
city was selected; 11 did not have a lawn service (code 0) and 19 had
a lawn service (code 1). Additional information available concerning
these 30 home owners includes family income (Income, in thousands
of dollars) and lawn size (Lawn Size, in thousands of square feet).
The PHStat output is given below:
TABLE 4-8
According to the record of the registrar’s office at a state university, 35% of the students
are freshman, 25% are sophomore, 16% are junior and the rest are senior. Among the
freshmen, sophomores, juniors and seniors, the portion of students who live in the
dormitory are, respectively, 80%, 60%, 30% and 20%.
Referring to Table 4-8, if a randomly selected student lives in the dormitory, what is the
probability that the student is not a freshman?
TABLE 19-6
A student wanted to find out the optimal strategy to study for a Business Statistics
exam. He constructed the following payoff table based on the mean amount of time he
needed to study every week for the course and the degree of difficulty of the exam.
From the information that he gathered from students who had taken the course, he
concluded that there was a 40% probability that the exam would be easy.
Referring to Table 19-6, what is the maximum amount that the student is willing to pay
to obtain perfect information?
TABLE 11-10
An agronomist wants to compare the crop yield of 3 varieties of chickpea seeds. She
plants all 3 varieties of the seeds on each of 5 different patches of fields. She then
measures the crop yield in bushels per acre. Treating this as a randomized block design,
the results are presented in the table that follows.
Referring to Table 11-10, what is the p-value of the test statistic for the randomized
block F test for the difference in the means?
TABLE 11-5
A hotel chain has identically small sized resorts in 5 locations in different small islands.
The data that follow resulted from analyzing the hotel occupancies on randomly
selected days in the 5 locations.
Analysis of Variance
* or p < 0.005, tabular value
Referring to Table 11-5, what is the p-value of the test statistic for Levene’s test for
homogeneity of variances?
The Dean of Students conducted a survey on campus. The gender of the student is an
example of a ________ variable.
TABLE 4-5
In a meat packaging plant Machine A accounts for 60% of the plant’s output, while
Machine B accounts for 40% of the plant’s output. In total, 4% of the packages are
improperly sealed. Also, 3% of the packages are from Machine A and are improperly
sealed.
Referring to Table 4-5, if a package is selected at random, the probability that it will be
properly sealed is ________.