,
,
,
, Introduction to Financial Statements 1-5
Ans: B; LO: 1.1-1; Difficulty: Easy; Type: MC
11. A study published in the Journal of Sports Science & Medicine tested the effectiveness of
the Power Balance © bracelet, which has been marketed as a way to improve balance,
flexibility, strength, and power through the use of hologram technology. Subjects, who
were all college athletes, completed tests of their athletic performance while wearing ei-
ther a Power Balance © bracelet or a plain rubber placebo bracelet. The bracelets were
covered with a wristband, so the athletes and those measuring their performance could
not see which bracelet was being worn. Only the researcher who analyzed the data knew
which measurements corresponded to the Power Balance © bracelet and which to the
placebo bracelet. Classify this study.
A. This study is not blinded.
B. This is a single-blind study.
C. This is a double-blind study.
D. There is not enough information to classify this study.
Ans: C; LO: 1.1-4; Difficulty: Easy; Type: MC
12. Which of the following is an experiment? Select all that apply.
A. Executives at a large department store chain selected 100 stores and randomly
assigned 50 of them to reduce their hours, opening an hour later than before;
hours for the other 50 stores were not changed. After six months, the executives
compared revenue for the two groups of stores.
B. A researcher recruited a group of American adults whose demographics were
similar to the American population. The researcher measured each subject’s
forced expiratory volume, an indicator of lung function. Then each subject was
asked whether or not they smoke cigarettes.
C. A survey was administered to a large group of high school students. The survey
asked whether the students were employed outside of school (in a paying job) and
how much sleep they got the night before (in hours).
Ans: A; LO: 1.1-2; Difficulty: Medium; Type: MS
13. A university professor teaches two sections of introductory statistics: one section meets at
8:00 am and the other meets at 11:00 am. She wants to evaluate the effectiveness of a
new method of teaching statistics compared to the standard method she has used in the
past. She flips a coin to assign her sections to teaching methods and determines that she
will use the standard method at 8:00 am and the new method at 11:00 am. At the end of
the term, she compares the final exam scores for the two sections. Which of the following
best describes the potential for confounding in this scenario?
A. Different students have different levels of talent and motivation, so it is impossible
to attribute differences in final exam scores to the teaching method.
B. The two sections may not be exactly the same size, which would lead to inappro-
priate comparisons between the treatment and control groups.
C. Students may find it difficult to pay attention at 8:00 am, which may negatively im-
pact the exam scores of those taught with the standard method.
D. Confounding is not a concern in this scenario, because the professor used random
assignment as part of the study design.
Ans: C; LO: 1.1-1; Difficulty: Medium; Type: MC
FOR INSTRUCTOR USE ONLY
, 1-6
14. True or False: The standard error of the residuals is a way to measure the amount of vari-
ation in the response variable that remains unexplained after applying the model.
Ans: True; LO: 1.1-1; Difficulty: Easy; Type: TF
15. True or False: Because of the possibility of confounding, you should always avoid using
causal language (action verbs like ―affect‖ and ―lead to‖) in your conclusions.
Ans: False; LO: 1.1-1; Difficulty: Easy Type: TF
Section 1.2: Quantifying Sources of Variation
LO1.2-1: Partitioning variation in the response variable into variation explained by the model and
unexplained variation.
LO1.2-2: Measuring percentage of variation explained.
LO1.2-3: Understanding effect size and practical significance.
Questions 1 through 3: Dog agility is a sport where trainers guide their dogs through an obsta-
cle course as quickly as possible. Two trainers, Abby and Lauren, have dogs participating
in agility competitions. Each dog completes the same agility course, and they measure the
time it takes each dog to complete the course (in seconds). The times for Abby’s three
dogs were 30, 40, and 50. The times for Lauren’s three dogs were 50, 60, and 70.
1. Calculate the Sum of Squares Total (SSTotal).
Solution: 30 50 40 50 50 50 50 50 60 50 70 50 1000
2 2 2 2 2 2
Ans: 1000 0; LO: 1.2-1; Difficulty: Medium; Type: Calc
2. Calculate the Sums of Squared Errors (SSError).
Solution: 30 40 40 40 50 40 50 60 60 60 70 60 400
2 2 2 2 2 2
Ans: 400 0; LO: 1.2-1; Difficulty: Medium; Type: Calc
3. Calculate the Sum of Squares for the Model (SSModel).
Solution: 40 50 40 50 40 50 60 50 60 50 60 50 600
2 2 2 2 2 2
Ans: 600 0; LO: 1.2-1; Difficulty: Medium; Type: Calc
Questions 4 and 5: Dog agility is a sport where trainers guide their dogs through an obstacle
FOR INSTRUCTOR USE ONLY
,
,
, Introduction to Financial Statements 1-5
Ans: B; LO: 1.1-1; Difficulty: Easy; Type: MC
11. A study published in the Journal of Sports Science & Medicine tested the effectiveness of
the Power Balance © bracelet, which has been marketed as a way to improve balance,
flexibility, strength, and power through the use of hologram technology. Subjects, who
were all college athletes, completed tests of their athletic performance while wearing ei-
ther a Power Balance © bracelet or a plain rubber placebo bracelet. The bracelets were
covered with a wristband, so the athletes and those measuring their performance could
not see which bracelet was being worn. Only the researcher who analyzed the data knew
which measurements corresponded to the Power Balance © bracelet and which to the
placebo bracelet. Classify this study.
A. This study is not blinded.
B. This is a single-blind study.
C. This is a double-blind study.
D. There is not enough information to classify this study.
Ans: C; LO: 1.1-4; Difficulty: Easy; Type: MC
12. Which of the following is an experiment? Select all that apply.
A. Executives at a large department store chain selected 100 stores and randomly
assigned 50 of them to reduce their hours, opening an hour later than before;
hours for the other 50 stores were not changed. After six months, the executives
compared revenue for the two groups of stores.
B. A researcher recruited a group of American adults whose demographics were
similar to the American population. The researcher measured each subject’s
forced expiratory volume, an indicator of lung function. Then each subject was
asked whether or not they smoke cigarettes.
C. A survey was administered to a large group of high school students. The survey
asked whether the students were employed outside of school (in a paying job) and
how much sleep they got the night before (in hours).
Ans: A; LO: 1.1-2; Difficulty: Medium; Type: MS
13. A university professor teaches two sections of introductory statistics: one section meets at
8:00 am and the other meets at 11:00 am. She wants to evaluate the effectiveness of a
new method of teaching statistics compared to the standard method she has used in the
past. She flips a coin to assign her sections to teaching methods and determines that she
will use the standard method at 8:00 am and the new method at 11:00 am. At the end of
the term, she compares the final exam scores for the two sections. Which of the following
best describes the potential for confounding in this scenario?
A. Different students have different levels of talent and motivation, so it is impossible
to attribute differences in final exam scores to the teaching method.
B. The two sections may not be exactly the same size, which would lead to inappro-
priate comparisons between the treatment and control groups.
C. Students may find it difficult to pay attention at 8:00 am, which may negatively im-
pact the exam scores of those taught with the standard method.
D. Confounding is not a concern in this scenario, because the professor used random
assignment as part of the study design.
Ans: C; LO: 1.1-1; Difficulty: Medium; Type: MC
FOR INSTRUCTOR USE ONLY
, 1-6
14. True or False: The standard error of the residuals is a way to measure the amount of vari-
ation in the response variable that remains unexplained after applying the model.
Ans: True; LO: 1.1-1; Difficulty: Easy; Type: TF
15. True or False: Because of the possibility of confounding, you should always avoid using
causal language (action verbs like ―affect‖ and ―lead to‖) in your conclusions.
Ans: False; LO: 1.1-1; Difficulty: Easy Type: TF
Section 1.2: Quantifying Sources of Variation
LO1.2-1: Partitioning variation in the response variable into variation explained by the model and
unexplained variation.
LO1.2-2: Measuring percentage of variation explained.
LO1.2-3: Understanding effect size and practical significance.
Questions 1 through 3: Dog agility is a sport where trainers guide their dogs through an obsta-
cle course as quickly as possible. Two trainers, Abby and Lauren, have dogs participating
in agility competitions. Each dog completes the same agility course, and they measure the
time it takes each dog to complete the course (in seconds). The times for Abby’s three
dogs were 30, 40, and 50. The times for Lauren’s three dogs were 50, 60, and 70.
1. Calculate the Sum of Squares Total (SSTotal).
Solution: 30 50 40 50 50 50 50 50 60 50 70 50 1000
2 2 2 2 2 2
Ans: 1000 0; LO: 1.2-1; Difficulty: Medium; Type: Calc
2. Calculate the Sums of Squared Errors (SSError).
Solution: 30 40 40 40 50 40 50 60 60 60 70 60 400
2 2 2 2 2 2
Ans: 400 0; LO: 1.2-1; Difficulty: Medium; Type: Calc
3. Calculate the Sum of Squares for the Model (SSModel).
Solution: 40 50 40 50 40 50 60 50 60 50 60 50 600
2 2 2 2 2 2
Ans: 600 0; LO: 1.2-1; Difficulty: Medium; Type: Calc
Questions 4 and 5: Dog agility is a sport where trainers guide their dogs through an obstacle
FOR INSTRUCTOR USE ONLY
