TEST BANK FOR I nt erme d i at e Stat i st i c a l I n ve st ig
at i o ns 1 e N at ha n T i nt le, Be th L. C h an ce , K a re n
Mc Ga ug h e y, S oma R o y, T o dd Swa n s o n, J i l l Va n
de r S t oe p
Chapte r 1 - 6
Chapte r 1
Intermediate Statistical Investigations Test Bank
Question types: FIB = Fill in the blank Calc = Calculation
Ma = Matching MS = Multiple select
MC = Multiple choice TF = True-false
CHAPTER 1 TERMINAL LEARNING OUTCOMES
TLO1-1: Apply the six-step investigative process in the context of a well-designed experiment.
TLO1-2: Partitioning variation in the response variable into variation explained by the model and
unexplained variation, and measuring and reporting the percentage of variation explained
TLO1-3: Assess the statistical significance of the difference between two groups on a quantitative
response variable using both simulation and theory-based approaches
TLO1-4: Compare more than two treatments on a quantitative response using both simulation
and theory-based approaches
TLO1-5: Apply Post-hoc analysis after significant F-test (pairwise differences, as well as
confidence and prediction intervals for single means)
TLO1-6: Understand statistical power and how it is impacted by sample size, variability within
groups, number of groups, and significance level
Section 1.1: Sources of Variation in an Experiment
LO1.1-1: Apply the six-step investigative process.
LO1.1-2: Distinguish experiments and observational studies.
LO1.1-3: Review basic study design principles such as inclusion criteria and random assignment.
LO1.1-4: Define terminology specific to an experimental study (e.g., treatments).
LO1.1-5: Produce a Sources of Variation diagram for an experiment.
Questions 1 through 3: A study published in Psychological Science in 2007 examined a possi-
ble link between mindset and health. The following is an excerpt from the abstract of the
article: ―84 female room attendants working in seven different hotels were measured on
physiological health variables affected by exercise. Those in the informed condition were
told that the work they do (cleaning hotel rooms) is good exercise and satisfies the Sur-
geon General's recommendations for an active lifestyle. Examples of how their work was
exercise were provided. Subjects in the control group were not given this information.‖
1. Identify the experimental units in this study.
A. The eighty-four room attendants
FOR INSTRUCTOR USE ONLY
,1-2
B. The seven different hotels
C. The physiological health variables
D. The two groups (informed and control)
Ans: A; LO: 1.1-4; Difficulty: Easy; Type: MC
2. The researchers chose to include room attendants from seven different hotels (as op-
posed to using stricter inclusion criteria that would limit the study to room attendants at
one particular hotel). Describe the consequences of this decision.
Using broader inclusion criteria may (increase/decrease) the amount of variation
in the observed health outcomes. However, this decision also (sup-
ports/limits) generalizability to a larger population of room attendants.
Ans: increase, supports; LO: 1.1-3; Difficulty: Medium; Type: FIB
3. Room attendants were randomly assigned to either the informed condition or the control
group. What is the most important reason for the random assignment?
A. Random assignment ensures that the study is double-blind.
B. Random assignment reduces the impact of outliers.
C. Random assignment creates two groups of room attendants that are as similar as
possible, which supports cause-and-effect conclusions.
D. Random assignment makes it possible to generalize the results to the population.
Ans: C; LO: 1.1-3; Difficulty: Medium; Type: MC
Questions 4 through 6: An online retailer is using an experiment to decide whether to modify
their website. When visitors type in the web address or click a link to the site, they are
randomly re-directed to one of two versions of the website: the version that has been in
use for the last year (version A) or an updated version (version B). The retailer’s goal is to
maximize the amount of time (in minutes) visitors stay on the site.
4. Identify the experimental units and variables. Note: One of the answer choices will not be
used.
Experimental units: A. Version of the website (A and B)
Explanatory variable: B: Online retailers
Response variable: C: Visitors to the website
D: Time spent on the website (in minutes)
Ans: Experimental units: C, Explanatory variable: A, Response variable: D; LO: 1.1-4;
Difficulty: Easy; Type: Ma
5. Consider two possible models for analyzing time spent on this retailer’s website.
Single-mean model:
A. Predicted timespent onsite 12.33, SEof residuals 4.64
Separate-means model:
FOR INSTRUCTOR USE ONLY
, 1-3
9.9 forVersion A
B. Predicted timespent on site , SE of residuals 3.98
14.7 forVersion B
Does the version of the website appear to explain any of the variation in time spent on the
site? Note: If more than one of these justifications is appropriate, select multiple answers.
A. Yes, because the mean time spent on the site is higher for Version B than for
Version A.
B. Yes, because the SE of the residuals is smaller for the separate-means model
than for the single-mean model.
C. No, because the mean time spent on the site is not the same for Version A and for
Version B.
D. No, because the SE of the residuals is smaller for the separate-means model than
for the single-mean model.
Ans: A, B; LO: 1.1-1; Difficulty: Medium; Type: MS
6. The researcher decides that the difference between Version A and Version B in this study
is meaningful. Is it reasonable to generalize these results to all customers of this retailer?
A. Yes, because visitors to the website were randomly assigned to either Version A
or Version B.
B. Yes, because the study’s inclusion criteria would exclude potential subjects who
are not customers.
C. It depends whether visitors to the website knew about the research question being
investigated. The study may not be double-blind.
D. It depends who visited the website during the study period. The sample may not
be representative.
Ans: D; LO: 1.1-1; Difficulty: Medium; Type: MC
Questions 7 through 8: Researchers at a university were interested in the effectiveness of a
calculus workshop program for students who fail Calculus I and need to retake the course.
As part of the study, students who were retaking Calculus I were allowed to enroll in a cal-
culus workshop at their own discretion. At the end of the grading term, all students (even
those with different instructors) took the same final exam. The researchers then compared
the scores for those who enrolled in the workshop while re-taking calculus to those who
re-took calculus without enrolling in the workshop.
7. Is this an experiment? Justify your answer.
A. Yes, this is an experiment, because there was a treatment group who enrolled in
the calculus workshop and a control group that did not.
B. Yes, this is an experiment, because the study was double-blind (as long as the
calculus teachers did not know which students enrolled in the workshop).
C. No, this is an observational study, because it does not take place in a laboratory or
other tightly controlled research environment.
D. No, this is an observational study, because the choice of whether to participate in
the workshop was made by the students not the researchers.
Ans: D; LO: 1.1-2; Difficulty: Easy; Type: MC
FOR INSTRUCTOR USE ONLY
, 1-4
8. Which of the following are sources of unexplained variation in this study? Select all that
apply.
A. Whether or not students enrolled in the workshop
B. Whether or not students had failed a calculus class in the past
C. Student attendance in class (number of absences)
D. Student motivation to study calculus
E. Calculus instructor
F. Difficulty of the final exam
Ans: C, D, E; LO: 1.1-5; Difficulty: Easy; Type: MS
9. A study published in Athletic Training examined the effects of three different types of knee
stabilizing braces on agility test speed. College football players from all different positions
(running back, wide receiver, linebacker, lineman, etc.) were recruited to participate in the
study. All players in the study had torn their ACL (anterior cruciate ligament) in the past,
and needed to wear a knee brace to play football. Agility tests were administered in an
outdoor football stadium, and the time to complete the test was recorded by a Lafayette
photoelectric Cell and Light Time Unit (in seconds).
Put the components of the study into the correct boxes in the Sources of Variation Dia-
gram. Note: Some boxes will include more than one answer.
Observed variation in: Sources of Sources of
explained variation unexplained variation
Inclusion criteria:
Design:
A. College football players from all different positions
B. Type of knee brace
C. Players’ current condition (health, mood, motivation, etc.)
D. Time to complete agility test (in seconds)
E. Measurement error
F. History of torn ACL and need for a knee brace
G. Details of the agility test
H. Players’ natural speed and agility
I. Environmental factors (weather, wind, etc.)
Ans: Observed variation in: D; Inclusion criteria: A, F; Design: G; Sources of explained
variation: B; Sources of unexplained variation: C, E, H, I; LO: 1.1-5; Difficulty: Medium;
Type: Ma
10. In a separate-means model, the standard error of the residuals can be thought of as the
typical deviation of an observed response from:
A. The residuals (prediction errors)
B. The response predicted by the model (group mean)
C. The overall mean of the response variable
D. The overall mean of the explanatory variable
FOR INSTRUCTOR USE ONLY
at i o ns 1 e N at ha n T i nt le, Be th L. C h an ce , K a re n
Mc Ga ug h e y, S oma R o y, T o dd Swa n s o n, J i l l Va n
de r S t oe p
Chapte r 1 - 6
Chapte r 1
Intermediate Statistical Investigations Test Bank
Question types: FIB = Fill in the blank Calc = Calculation
Ma = Matching MS = Multiple select
MC = Multiple choice TF = True-false
CHAPTER 1 TERMINAL LEARNING OUTCOMES
TLO1-1: Apply the six-step investigative process in the context of a well-designed experiment.
TLO1-2: Partitioning variation in the response variable into variation explained by the model and
unexplained variation, and measuring and reporting the percentage of variation explained
TLO1-3: Assess the statistical significance of the difference between two groups on a quantitative
response variable using both simulation and theory-based approaches
TLO1-4: Compare more than two treatments on a quantitative response using both simulation
and theory-based approaches
TLO1-5: Apply Post-hoc analysis after significant F-test (pairwise differences, as well as
confidence and prediction intervals for single means)
TLO1-6: Understand statistical power and how it is impacted by sample size, variability within
groups, number of groups, and significance level
Section 1.1: Sources of Variation in an Experiment
LO1.1-1: Apply the six-step investigative process.
LO1.1-2: Distinguish experiments and observational studies.
LO1.1-3: Review basic study design principles such as inclusion criteria and random assignment.
LO1.1-4: Define terminology specific to an experimental study (e.g., treatments).
LO1.1-5: Produce a Sources of Variation diagram for an experiment.
Questions 1 through 3: A study published in Psychological Science in 2007 examined a possi-
ble link between mindset and health. The following is an excerpt from the abstract of the
article: ―84 female room attendants working in seven different hotels were measured on
physiological health variables affected by exercise. Those in the informed condition were
told that the work they do (cleaning hotel rooms) is good exercise and satisfies the Sur-
geon General's recommendations for an active lifestyle. Examples of how their work was
exercise were provided. Subjects in the control group were not given this information.‖
1. Identify the experimental units in this study.
A. The eighty-four room attendants
FOR INSTRUCTOR USE ONLY
,1-2
B. The seven different hotels
C. The physiological health variables
D. The two groups (informed and control)
Ans: A; LO: 1.1-4; Difficulty: Easy; Type: MC
2. The researchers chose to include room attendants from seven different hotels (as op-
posed to using stricter inclusion criteria that would limit the study to room attendants at
one particular hotel). Describe the consequences of this decision.
Using broader inclusion criteria may (increase/decrease) the amount of variation
in the observed health outcomes. However, this decision also (sup-
ports/limits) generalizability to a larger population of room attendants.
Ans: increase, supports; LO: 1.1-3; Difficulty: Medium; Type: FIB
3. Room attendants were randomly assigned to either the informed condition or the control
group. What is the most important reason for the random assignment?
A. Random assignment ensures that the study is double-blind.
B. Random assignment reduces the impact of outliers.
C. Random assignment creates two groups of room attendants that are as similar as
possible, which supports cause-and-effect conclusions.
D. Random assignment makes it possible to generalize the results to the population.
Ans: C; LO: 1.1-3; Difficulty: Medium; Type: MC
Questions 4 through 6: An online retailer is using an experiment to decide whether to modify
their website. When visitors type in the web address or click a link to the site, they are
randomly re-directed to one of two versions of the website: the version that has been in
use for the last year (version A) or an updated version (version B). The retailer’s goal is to
maximize the amount of time (in minutes) visitors stay on the site.
4. Identify the experimental units and variables. Note: One of the answer choices will not be
used.
Experimental units: A. Version of the website (A and B)
Explanatory variable: B: Online retailers
Response variable: C: Visitors to the website
D: Time spent on the website (in minutes)
Ans: Experimental units: C, Explanatory variable: A, Response variable: D; LO: 1.1-4;
Difficulty: Easy; Type: Ma
5. Consider two possible models for analyzing time spent on this retailer’s website.
Single-mean model:
A. Predicted timespent onsite 12.33, SEof residuals 4.64
Separate-means model:
FOR INSTRUCTOR USE ONLY
, 1-3
9.9 forVersion A
B. Predicted timespent on site , SE of residuals 3.98
14.7 forVersion B
Does the version of the website appear to explain any of the variation in time spent on the
site? Note: If more than one of these justifications is appropriate, select multiple answers.
A. Yes, because the mean time spent on the site is higher for Version B than for
Version A.
B. Yes, because the SE of the residuals is smaller for the separate-means model
than for the single-mean model.
C. No, because the mean time spent on the site is not the same for Version A and for
Version B.
D. No, because the SE of the residuals is smaller for the separate-means model than
for the single-mean model.
Ans: A, B; LO: 1.1-1; Difficulty: Medium; Type: MS
6. The researcher decides that the difference between Version A and Version B in this study
is meaningful. Is it reasonable to generalize these results to all customers of this retailer?
A. Yes, because visitors to the website were randomly assigned to either Version A
or Version B.
B. Yes, because the study’s inclusion criteria would exclude potential subjects who
are not customers.
C. It depends whether visitors to the website knew about the research question being
investigated. The study may not be double-blind.
D. It depends who visited the website during the study period. The sample may not
be representative.
Ans: D; LO: 1.1-1; Difficulty: Medium; Type: MC
Questions 7 through 8: Researchers at a university were interested in the effectiveness of a
calculus workshop program for students who fail Calculus I and need to retake the course.
As part of the study, students who were retaking Calculus I were allowed to enroll in a cal-
culus workshop at their own discretion. At the end of the grading term, all students (even
those with different instructors) took the same final exam. The researchers then compared
the scores for those who enrolled in the workshop while re-taking calculus to those who
re-took calculus without enrolling in the workshop.
7. Is this an experiment? Justify your answer.
A. Yes, this is an experiment, because there was a treatment group who enrolled in
the calculus workshop and a control group that did not.
B. Yes, this is an experiment, because the study was double-blind (as long as the
calculus teachers did not know which students enrolled in the workshop).
C. No, this is an observational study, because it does not take place in a laboratory or
other tightly controlled research environment.
D. No, this is an observational study, because the choice of whether to participate in
the workshop was made by the students not the researchers.
Ans: D; LO: 1.1-2; Difficulty: Easy; Type: MC
FOR INSTRUCTOR USE ONLY
, 1-4
8. Which of the following are sources of unexplained variation in this study? Select all that
apply.
A. Whether or not students enrolled in the workshop
B. Whether or not students had failed a calculus class in the past
C. Student attendance in class (number of absences)
D. Student motivation to study calculus
E. Calculus instructor
F. Difficulty of the final exam
Ans: C, D, E; LO: 1.1-5; Difficulty: Easy; Type: MS
9. A study published in Athletic Training examined the effects of three different types of knee
stabilizing braces on agility test speed. College football players from all different positions
(running back, wide receiver, linebacker, lineman, etc.) were recruited to participate in the
study. All players in the study had torn their ACL (anterior cruciate ligament) in the past,
and needed to wear a knee brace to play football. Agility tests were administered in an
outdoor football stadium, and the time to complete the test was recorded by a Lafayette
photoelectric Cell and Light Time Unit (in seconds).
Put the components of the study into the correct boxes in the Sources of Variation Dia-
gram. Note: Some boxes will include more than one answer.
Observed variation in: Sources of Sources of
explained variation unexplained variation
Inclusion criteria:
Design:
A. College football players from all different positions
B. Type of knee brace
C. Players’ current condition (health, mood, motivation, etc.)
D. Time to complete agility test (in seconds)
E. Measurement error
F. History of torn ACL and need for a knee brace
G. Details of the agility test
H. Players’ natural speed and agility
I. Environmental factors (weather, wind, etc.)
Ans: Observed variation in: D; Inclusion criteria: A, F; Design: G; Sources of explained
variation: B; Sources of unexplained variation: C, E, H, I; LO: 1.1-5; Difficulty: Medium;
Type: Ma
10. In a separate-means model, the standard error of the residuals can be thought of as the
typical deviation of an observed response from:
A. The residuals (prediction errors)
B. The response predicted by the model (group mean)
C. The overall mean of the response variable
D. The overall mean of the explanatory variable
FOR INSTRUCTOR USE ONLY
