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HSC 404 - Final Exam (Ch 9, 10, 11, 12, 13,
15, 16) Questions and Correct Answers/
Latest Update / Already Graded
The strategy which is not aimed at reducing selection bias is:
A. Development of an explicit case definition
B. Standardized protocol for structured interviews
C. Enrollment of all cases in a defined time and region
D. Encouragement of high participation rates
Ans: D
Recall bias is most likely to occur in:
A. Case control studies
B. Prospective cohort studies
C. Experimental studies
D. All of the above
E. None of the above
Ans: A
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The purpose of a double-blind study is to:
A. Reduce the effects of sampling variation
B. Avoid observer bias and sampling variation
C. Achieve comparability of cases and controls
D. Avoid observer and interviewee bias
E. Avoid interviewee bias and sampling variation
Ans: D
In a study to determine the incidence of chronic disease, 150 people
were examined at the end of a three-year period. Twelve cases were
found, giving a cumulative risk of 8%. Fifty other members of the initial
cohort could not be examined; 20 of these 50 could not be examined
because they died.
Which source of bias may have affected the study?
A. Information bias: interviewer/abstractor bias
B. Hawthorne Effect
C. Selection bias: survival bias
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D. Information bias: recall bias
Ans: C
Which of the following is not a type of selection bias in cohort studies:
A. Loss to follow-up
B. None of the above
C. Healthy worker effect
D. Interviewer bias
Ans: D
Surgeons at Hospital A report that the mortality rate at the end of a
one-year follow-up after a new coronary bypass procedure is 15%. At
Hospital B, the surgeons report a one-year mortality rate of 8% for the
same procedure. Before concluding that the surgeons at Hospital B
have vastly superior skill, which of the following possible confounders
would you examine?
Ans: A. The severity (stage) of the disease of the patients at
the two hospitals at baseline
B. The starting point of the one-year follow-up at both hospitals
C. Different in the post-operative care at the two hospitals
D. Equally through follow-up for mortality
All rights reserved © 2025/ 2026 |
HSC 404 - Final Exam (Ch 9, 10, 11, 12, 13,
15, 16) Questions and Correct Answers/
Latest Update / Already Graded
The strategy which is not aimed at reducing selection bias is:
A. Development of an explicit case definition
B. Standardized protocol for structured interviews
C. Enrollment of all cases in a defined time and region
D. Encouragement of high participation rates
Ans: D
Recall bias is most likely to occur in:
A. Case control studies
B. Prospective cohort studies
C. Experimental studies
D. All of the above
E. None of the above
Ans: A
All rights reserved © 2025/ 2026 |
, Page |2
The purpose of a double-blind study is to:
A. Reduce the effects of sampling variation
B. Avoid observer bias and sampling variation
C. Achieve comparability of cases and controls
D. Avoid observer and interviewee bias
E. Avoid interviewee bias and sampling variation
Ans: D
In a study to determine the incidence of chronic disease, 150 people
were examined at the end of a three-year period. Twelve cases were
found, giving a cumulative risk of 8%. Fifty other members of the initial
cohort could not be examined; 20 of these 50 could not be examined
because they died.
Which source of bias may have affected the study?
A. Information bias: interviewer/abstractor bias
B. Hawthorne Effect
C. Selection bias: survival bias
All rights reserved © 2025/ 2026 |
, Page |3
D. Information bias: recall bias
Ans: C
Which of the following is not a type of selection bias in cohort studies:
A. Loss to follow-up
B. None of the above
C. Healthy worker effect
D. Interviewer bias
Ans: D
Surgeons at Hospital A report that the mortality rate at the end of a
one-year follow-up after a new coronary bypass procedure is 15%. At
Hospital B, the surgeons report a one-year mortality rate of 8% for the
same procedure. Before concluding that the surgeons at Hospital B
have vastly superior skill, which of the following possible confounders
would you examine?
Ans: A. The severity (stage) of the disease of the patients at
the two hospitals at baseline
B. The starting point of the one-year follow-up at both hospitals
C. Different in the post-operative care at the two hospitals
D. Equally through follow-up for mortality
All rights reserved © 2025/ 2026 |
