HSC 404, FINAL EXAM UPDATED QUESTIONS
AND CORRECT ANSWERS
Question:
1. The population etiologic fraction is a measure of the proportion of the disease rate in a population
attributable to the exposure of interest. This measure of effect is influenced by:
Answer:
-the relative risk of the disease in exposed individuals versus unexposed individuals AND
-the prevalence of the exposure in the population
Question:
2. If it is accepted than an observed association is a causal one, an estimate of the impact that a successful
preventative program might have, can be derived from:
Answer:
attributable risk
Question:
3. When assessing a positive relationship between alcohol consumption and oral cancer using a
case-control study, increasing the sample size of the study will result in:
A. -a lower p value
B. -a greater odds ratio
C. -a smaller 95% confidence interval
D. -a higher disease prevalence
Answer:
-none of the above
Question:
4. An attributable-risk percent of 80% was calculated for the association between smoking and lung cancer
death. The best interpretation of this statistic would be:
Answer:
Of those dying of lung cancer who smoke, 80% of those deaths are attributed to their smoking, assuming a
causal association exists.
Question:
5. Several studies have found that approximately 85% of cases of lung cancer are due to cigarette smoking.
This is an example of:
Answer:
attributable risk
Question:
6. Selection bias is most likely to occur in:
Answer:
both retrospective cohort studies and case control studies
, Question:
7. Recall bias is most likely to occur in:
Answer:
case control studies
Question:
8. 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?
Answer:
selection bias: survival bias
Question:
9. You are investigating the role of physical activity in heart disease and suggest that physical activity
protects against having a heart attack. While presenting these data to your colleagues, someone asks if you
could have thought about confounders such as factor X. This factor X could have confounded your
interpretation of the data if it:
Answer:
is a factor associated with physical activity and heart disease
Question:
10. The strategy which is NOT aimed at reducing selection bias is:
Answer:
Standardized protocol for structured interviews
Question:
11. Which is NOT a method for controlling the effects of confounding in epidemiological studies?
Answer:
Blinding
Question:
12. The purpose of a double-blind study is to:
Answer:
avoid observer and interviewee bias
Question:
13. In a survey which uses lay interviewers to interview one person about his or her health and the health
of household members, the sources of error include:
Answer:
-the person with disease has had no symptoms and is not aware of the disease
-the respondent provides the information but the interviewer doesn't record it or records it incorrectly
-the interviewer doesn't ask the questions that he or she is instructed to ask, or asks them incorrectly
-the person has had symptoms and has had medical attention but does not know the name of the disease
AND CORRECT ANSWERS
Question:
1. The population etiologic fraction is a measure of the proportion of the disease rate in a population
attributable to the exposure of interest. This measure of effect is influenced by:
Answer:
-the relative risk of the disease in exposed individuals versus unexposed individuals AND
-the prevalence of the exposure in the population
Question:
2. If it is accepted than an observed association is a causal one, an estimate of the impact that a successful
preventative program might have, can be derived from:
Answer:
attributable risk
Question:
3. When assessing a positive relationship between alcohol consumption and oral cancer using a
case-control study, increasing the sample size of the study will result in:
A. -a lower p value
B. -a greater odds ratio
C. -a smaller 95% confidence interval
D. -a higher disease prevalence
Answer:
-none of the above
Question:
4. An attributable-risk percent of 80% was calculated for the association between smoking and lung cancer
death. The best interpretation of this statistic would be:
Answer:
Of those dying of lung cancer who smoke, 80% of those deaths are attributed to their smoking, assuming a
causal association exists.
Question:
5. Several studies have found that approximately 85% of cases of lung cancer are due to cigarette smoking.
This is an example of:
Answer:
attributable risk
Question:
6. Selection bias is most likely to occur in:
Answer:
both retrospective cohort studies and case control studies
, Question:
7. Recall bias is most likely to occur in:
Answer:
case control studies
Question:
8. 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?
Answer:
selection bias: survival bias
Question:
9. You are investigating the role of physical activity in heart disease and suggest that physical activity
protects against having a heart attack. While presenting these data to your colleagues, someone asks if you
could have thought about confounders such as factor X. This factor X could have confounded your
interpretation of the data if it:
Answer:
is a factor associated with physical activity and heart disease
Question:
10. The strategy which is NOT aimed at reducing selection bias is:
Answer:
Standardized protocol for structured interviews
Question:
11. Which is NOT a method for controlling the effects of confounding in epidemiological studies?
Answer:
Blinding
Question:
12. The purpose of a double-blind study is to:
Answer:
avoid observer and interviewee bias
Question:
13. In a survey which uses lay interviewers to interview one person about his or her health and the health
of household members, the sources of error include:
Answer:
-the person with disease has had no symptoms and is not aware of the disease
-the respondent provides the information but the interviewer doesn't record it or records it incorrectly
-the interviewer doesn't ask the questions that he or she is instructed to ask, or asks them incorrectly
-the person has had symptoms and has had medical attention but does not know the name of the disease
