STA 2e: Chapter 6 Review
MATCHING
Name _______KEY_________________________
Match each word or phrase with its definition.
K 1. anonymity
A. experiment which studies the effectiveness of medical
treatments on actual patients
M 2. block design
B. an experiment in which neither the subjects nor the people
who work with them know which treatment each subject is
receiving
A 3. clinical trial
C. a study which deliberately imposes some treatment on
individuals in order to observe their responses
P 4. confidentiality
D. a variable that has an important effect on the relationship
among the variables in a study but is not one of the
variables being studied
E 5. confounding
E. the influence of the explanatory variable cannot be
distinguished from the influence of a lurking variable
T 6. control group
F. a variable that we think explains or causes changes in the
response variables
O 7. completely randomized experiment
G. a dummy treatment with no active ingredients
B 8. double-blind experiment
H. the individuals studied in an experiment
C 9. experiment
I.
an observed effect so large that it would rarely occur by
chance
F10. explanatory variable
J.
a variable that measures an outcome or result of a study
D11. lurking variable
K. when the names of the subjects are not known to even the
director of a study
N12. matched pairs design
L. favorable response to a dummy treatment
Q13. nonadherers
M. subjects are first grouped into similar traits and then
randomization is carried out separately within each group
G14. placebo
N. experimental technique comparing pairs of subjects that
are alike as much as possible when each receives a
different treatment
L15. placebo effect
O. experiment in which all subjects are randomly assigned to
treatments
S16. randomized comparative experiment
P. policy of keeping all collected data about the individual
subjects private
J17. response variable
Q. subjects who do not follow the experimental treatment
I 18. statistically significant
R. any specific experimental condition applied to the subjects
H19. subjects
S. a study comparing two or more treatments, using chance
to decide which subjects get each treatment, and using
enough subjects so that the effects of chance variations
between the groups are small
R20. treatment
T. the group in an experiment which receives the placebo
treatment or a treatment which is already on the market
STA 2e: Chapter 6 Review
MULTIPLE CHOICE/SHORT ANSWER
Name ________KEY________________
For #1 – 2: 40 boys and 40 girls with ADD
(Attention Deficit Disorder) were selected to
participate in a study of a new drug’s effectively
in controlling ADD. The boys were randomly
divided into 2 groups and the girls were randomly
divided into 2 groups. One group of each gender
received the new drug, while the other group
received the old drug.
5. What is the response variable?
A
B
C
D
E
1. This study was ? .
A
B
C
D
a simple random sample
a completely randomized experiment
a matched-pairs experiment
a block design experiment, blocked on
severity of ADD
E a block design experiment, blocked on
gender
6. In the problem, what does “not statistically
significant” mean?
A
B
2. What is the explanatory variable?
A
B
C
D
E
reading test scores at the beginning
reading test scores at the end
difference in beginning and ending reading
scores
the drug
gender
C
D
E
7.
For #3 – 6: A pharmaceutical company wants to
test a new diet drug.
They recruited 20
overweight people to participate in the study.
Ten people were randomly assigned to receive
the new drug and the other 10 to receive a
placebo. All 20 participants were weighed before
treatment and then again after 12 weeks of
treatment. The change in weight was found for
each participant.
The results were not
statistically significant.
an observational study
a simple random sample
an experiment, but not randomized
a block design experiment
randomized comparative experiment
B
C
D
E
4. What is the population of interest?
A
B
C
D
E
the 10 overweight people who received the
new drug
the 20 overweight people who participated in
the study
all overweight people
all overweight people taking diet drugs
all people
8.
the observed difference could plausibly have
occurred by chance
the observed difference could not plausibly
have occurred by chance
the study was not well-designed
randomization was used in creating the
groups
the two groups lost the same amount of
weight
____________________________
Which of the following is true about a doubleblind experiment?
A
3. This study was ? .
A
B
C
D
E
the beginning weight of each participant
the weight of each participant after 12 weeks
the difference in weight of each participant
after 12 weeks
the 10 overweight people who took the new
drug
the 20 overweight people who participated in
the study
each subject in the experiment is given two
sets of blindfolds
both the subjects and the evaluators are
each given blindfolds
the subjects do not know which treatment
group they are in
the evaluators do not know which treatment
group the subjects are in
neither the subjects not the evaluators know
which treatment group the subjects are in
An experiment is to be conducted to determine if
a new drug for high blood pressure is more
effective than the present drug. There is a
concern that men and women will react
differently to the drug.
Therefore, the
experimenter should ? .
A use only men in the experiment
B use only women in the experiment
C just randomly assign all participants to the
two groups
D first block on gender
E assign half the men and half the women to
each group
9. Eight members of student council all want to be
on the Prom Committee, but only three will be
selected. Some of the students have been
studying Statistics and decide that a random digit
table would be the fair way to choose the three
students. Each student is assigned a digit as
follows:
1 Amy
5 Chelsea
2 Beth
6 Jasmin
3 Dave
7 Jose
12. We want to know if a new diet pill is more
effective than the current pill. We locate 20 pairs
of overweight, identical twins and randomly
assign one twin to each pill. After 12 weeks, we
find the difference in weight loss between twins.
This study is best described as ? .
A
B
C
D
4 Jay
8 Tom
Use this partial random digit table to deter-mine
which three students will form the committee
E
an observational study
a randomized comparative experiment
a matched-pairs experiment
a block design experiment, blocking on
weight
a comparative experiment with no
randomization
99404 70708 41098 43563
A Dave, Jay, Beth
C Jay, Jose, Tom
B
D
Amy, Beth, Jay
Jay, Jay, Jose
13. If subjects in an experiment are separated into
groups of men and women before the
randomization is done, then we should think of
gender as a(n) ? variable.
10. A toy manufacturer wants to test 3 different types
of hinges for a toy box. Since boys and girls tend
to play differently with toys, how should this study
be conducted?
A
B
C
D
E
as an observational study
as a randomized comparative experiment
as a matched-pairs experiment
as a block design experiment, blocking on
hinges
as a block design experiment, blocking on
gender
11. We want to test a new fertilizer, Giant Grow, on
three types of vegetables: tomatoes, squash,
and cucumbers. Is Giant Grow better than the
currently used fertilizer or is it better than using
no fertilizer at all? How many experimental
groups would we need?
A
D
2
5
B
E
3
6
C
A
C
E
blocking
confounding
response
B
D
explanatory
random
14. Why is blocking used in experiment?
A
B
C
D
E
to make the results more statistically
significant
to minimize the placebo effect
to minimize differences between treatment
groups
to reduce variability
to reduce bias
15. If we want to show that one variable causes
another variable, then we should use a(n) ? .
4
A
B
C
D
an observational study
a sample survey
an experiment
a completely randomized comparative
experiment
Short Answer
16. Can an experiment always be blinded? Explain your answer. ………No, if exercise or meditation is the
explanatory variable, participants will know they are in a treatment group
17. Give an example of when blinding is not necessary. ……Subjects are animals and plants……
18. Name the three basic principles of experimental design.
1) randomization…… 2) ……control……… 3) ……having enough subjects………
19. Refer to #11 above. Name a possible confounding variable in this experiment.
sunlight used; soil
…amount of water or