POPM 3240 Midterm 2 Questions with All
Solved Solutions 2026/2027.
In a study of Parkinson's disease, 100 volunteers had incisions made through their skulls. The
patients were randomly allocated to one of 2 groups. One group had a new drug inserted into
the brain. In the other group, the skulls were closed with no treatment given. The patients did
not know who received the drug. Physical condition of all patients was assessed over the next
several months, both by patient - report and by a researcher who was not aware of the patients'
group allocation. In the follow-up period, all 100 volunteers showed similar improvements in
physical condition.
Which of the following is exemplified by the above description?
A. Sampling error
B. The control group effect
C. The effect of a treatment
D. The placebo effect
E. None of the above - Answer D
In a study of Parkinson's disease, 100 volunteers had incisions made through their skulls. The
patients were randomly allocated to one of 2 groups. One group had a new drug inserted into
the brain. In the other group, the skulls were closed with no treatment given. The patients did
not know who received the drug. Physical condition of all patients was assessed over the next
several months, both by patient - report and by a researcher who was not aware of the patients'
group allocation. In the follow-up period, all 100 volunteers showed similar improvements in
physical condition.
Which of the following approaches to validity was used in this study?
A. Matching
B. Replication
C. Stratified random sampling
D. Single blinding
E. Double blinding - Answer E
The major purpose of random allocation in clinical trials is to:
A. Reduce selection bias in the allocation of treatment
B. Facilitate the measurement of outcome variables
C. Help ensure that study subjects are representative of the general population
, D. Facilitate double blinding
E. Ensure that the study groups have comparable baseline characteristics - Answer E
A patient says to his physician, "Doc, it is so hard for me to quit drinking. But if I did, how much
would this reduce the risk of me getting liver disease?". Which of the following statistics would
best help answer this question?
A. Risk difference
B. Population attributable risk
C. Population attributable fraction
D. Relative risk
E. Odds ratio - Answer A
Which of the following statement about selection of controls in a case-
control study is correct?
A. Matching can be done to reduce confounding bias
B. It is best to identify controls with conditions that are related to the outcome in the case-
control study
C. Randomization can help ensure comparability of cases and controls
D. It is less important to ensure comparability of cases and controls in a case-control study than
comparability of study arms in a randomized controlled trial
E. More than one of the above is correct - Answer A
A study was started in 2001, whereby 3,000 youth in Canada were asked about their use of
marijuana. The occurrence of cases of schizophrenia amongst these individuals between 2010
and 2017 was recorded. This is an example of:
A. A cross-sectional study
B. A prospective cohort study
C. A case-control study
D. A retrospective cohort study
E. An experimental study - Answer B
A pharmaceutical company reported
the following in an article: "700 subjects with cold sores were treated
Solved Solutions 2026/2027.
In a study of Parkinson's disease, 100 volunteers had incisions made through their skulls. The
patients were randomly allocated to one of 2 groups. One group had a new drug inserted into
the brain. In the other group, the skulls were closed with no treatment given. The patients did
not know who received the drug. Physical condition of all patients was assessed over the next
several months, both by patient - report and by a researcher who was not aware of the patients'
group allocation. In the follow-up period, all 100 volunteers showed similar improvements in
physical condition.
Which of the following is exemplified by the above description?
A. Sampling error
B. The control group effect
C. The effect of a treatment
D. The placebo effect
E. None of the above - Answer D
In a study of Parkinson's disease, 100 volunteers had incisions made through their skulls. The
patients were randomly allocated to one of 2 groups. One group had a new drug inserted into
the brain. In the other group, the skulls were closed with no treatment given. The patients did
not know who received the drug. Physical condition of all patients was assessed over the next
several months, both by patient - report and by a researcher who was not aware of the patients'
group allocation. In the follow-up period, all 100 volunteers showed similar improvements in
physical condition.
Which of the following approaches to validity was used in this study?
A. Matching
B. Replication
C. Stratified random sampling
D. Single blinding
E. Double blinding - Answer E
The major purpose of random allocation in clinical trials is to:
A. Reduce selection bias in the allocation of treatment
B. Facilitate the measurement of outcome variables
C. Help ensure that study subjects are representative of the general population
, D. Facilitate double blinding
E. Ensure that the study groups have comparable baseline characteristics - Answer E
A patient says to his physician, "Doc, it is so hard for me to quit drinking. But if I did, how much
would this reduce the risk of me getting liver disease?". Which of the following statistics would
best help answer this question?
A. Risk difference
B. Population attributable risk
C. Population attributable fraction
D. Relative risk
E. Odds ratio - Answer A
Which of the following statement about selection of controls in a case-
control study is correct?
A. Matching can be done to reduce confounding bias
B. It is best to identify controls with conditions that are related to the outcome in the case-
control study
C. Randomization can help ensure comparability of cases and controls
D. It is less important to ensure comparability of cases and controls in a case-control study than
comparability of study arms in a randomized controlled trial
E. More than one of the above is correct - Answer A
A study was started in 2001, whereby 3,000 youth in Canada were asked about their use of
marijuana. The occurrence of cases of schizophrenia amongst these individuals between 2010
and 2017 was recorded. This is an example of:
A. A cross-sectional study
B. A prospective cohort study
C. A case-control study
D. A retrospective cohort study
E. An experimental study - Answer B
A pharmaceutical company reported
the following in an article: "700 subjects with cold sores were treated
