EPI EXAM 4 ACTUAL QUESTIONS AND ANSWERS
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: - CORRECT
ANSWER✅✅The relative risk of the disease in exposed individuals versus unexposed individuals and the
prevalence of the exposure in the population
If it is accepted that an observed association is a causal one, an estimate of the impact that a successful
preventive program might have, can be derived from: - CORRECT ANSWER✅✅Attributable risk
Which statement is NOT true concerning attributable risk - CORRECT ANSWER✅✅The ratio of incidence
of a disease among exposed individuals to the incidence among non-exposed individuals
An attributable risk percent of 85% was calculated for the association between smoking and lung cancer
death. Which of the following provides the best interpretation of this - CORRECT ANSWER✅✅Of those
dying of lung cancer who smoke, 85% of those deaths are attributed to their smoking, assuming a causal
association exists
Suppose that the population attributable risk percent in an analysis assessing the relationship between
physical inactivity and heart disease was 30% (assume there is a causal association between physical
inactivity and heart disease) Which of the following best defines this result - CORRECT
ANSWER✅✅Approx. 30% of heart disease is attributed to physical inactivity
T OR F The purpose of matching in a case-control study is to select the controls in such a way that the
control group has the same distribution as the cases with respect to certain confounding variables -
CORRECT ANSWER✅✅TRUE
In a study to determine the incidence of a chronic disease, 150 people were examined at the end of a 3-
year period. 12 cases were found, giving a cumulative risk of 8%. 50 other members of initial cohort
couldn't be examined; 20 of these 50 couldn't be examined because they died. Which source of bias may
have affected the study? - CORRECT ANSWER✅✅Selection bias: survival bias
You are investigating the role of physical activity in heart disease and suggest that physical activity
protects against having a heart attack. While presenting the data to your colleagues , someone asks if
you thought about confounders such as factor X. This factor X could have confounded your
, interpretation of the data if it: - CORRECT ANSWER✅✅Is a factor associated with physical activity and
heart disease
The strategy which is NOT aimed at reducing selection bias is: - CORRECT ANSWER✅✅Standardized
protocol for structured interviews
Which of the following is NOT a method for controlling the effects of confounding in epidemiological
studies? - CORRECT ANSWER✅✅Blinding
The purpose of a double-blind study is to: - CORRECT ANSWER✅✅Avoid observer and interviewee bias
In a survey which used lay interviewers to interview one person about his or her health and the health
of household members, the sources of error include: - CORRECT ANSWER✅✅The person with disease
has had no symptoms and is not aware of the disease
The respondent provides the information but the interviewers doesn't record it or records 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
An epidemiological experiment is performed in which one group is exposed to a suspected factor and
the other is not. All individuals with an odd hospital admission number are assigned to the second
group. The main purpose of this procedure is to: - CORRECT ANSWER✅✅Improve the likelihood that
the two groups will be comparable with regard to known and unknown confounding factors
A double-blind study of vaccine is one in which - CORRECT ANSWER✅✅Neither observers nor subjects
know which subject receives the vaccine and which receives a placebo
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 following possible confounders would you examine? - CORRECT ANSWER✅✅The severity (stage) of
disease of the patients at the 2 hospitals at baseline
The starting point of the 1 year follow up at both hospitals (after operation vs. after discharge)
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: - CORRECT
ANSWER✅✅The relative risk of the disease in exposed individuals versus unexposed individuals and the
prevalence of the exposure in the population
If it is accepted that an observed association is a causal one, an estimate of the impact that a successful
preventive program might have, can be derived from: - CORRECT ANSWER✅✅Attributable risk
Which statement is NOT true concerning attributable risk - CORRECT ANSWER✅✅The ratio of incidence
of a disease among exposed individuals to the incidence among non-exposed individuals
An attributable risk percent of 85% was calculated for the association between smoking and lung cancer
death. Which of the following provides the best interpretation of this - CORRECT ANSWER✅✅Of those
dying of lung cancer who smoke, 85% of those deaths are attributed to their smoking, assuming a causal
association exists
Suppose that the population attributable risk percent in an analysis assessing the relationship between
physical inactivity and heart disease was 30% (assume there is a causal association between physical
inactivity and heart disease) Which of the following best defines this result - CORRECT
ANSWER✅✅Approx. 30% of heart disease is attributed to physical inactivity
T OR F The purpose of matching in a case-control study is to select the controls in such a way that the
control group has the same distribution as the cases with respect to certain confounding variables -
CORRECT ANSWER✅✅TRUE
In a study to determine the incidence of a chronic disease, 150 people were examined at the end of a 3-
year period. 12 cases were found, giving a cumulative risk of 8%. 50 other members of initial cohort
couldn't be examined; 20 of these 50 couldn't be examined because they died. Which source of bias may
have affected the study? - CORRECT ANSWER✅✅Selection bias: survival bias
You are investigating the role of physical activity in heart disease and suggest that physical activity
protects against having a heart attack. While presenting the data to your colleagues , someone asks if
you thought about confounders such as factor X. This factor X could have confounded your
, interpretation of the data if it: - CORRECT ANSWER✅✅Is a factor associated with physical activity and
heart disease
The strategy which is NOT aimed at reducing selection bias is: - CORRECT ANSWER✅✅Standardized
protocol for structured interviews
Which of the following is NOT a method for controlling the effects of confounding in epidemiological
studies? - CORRECT ANSWER✅✅Blinding
The purpose of a double-blind study is to: - CORRECT ANSWER✅✅Avoid observer and interviewee bias
In a survey which used lay interviewers to interview one person about his or her health and the health
of household members, the sources of error include: - CORRECT ANSWER✅✅The person with disease
has had no symptoms and is not aware of the disease
The respondent provides the information but the interviewers doesn't record it or records 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
An epidemiological experiment is performed in which one group is exposed to a suspected factor and
the other is not. All individuals with an odd hospital admission number are assigned to the second
group. The main purpose of this procedure is to: - CORRECT ANSWER✅✅Improve the likelihood that
the two groups will be comparable with regard to known and unknown confounding factors
A double-blind study of vaccine is one in which - CORRECT ANSWER✅✅Neither observers nor subjects
know which subject receives the vaccine and which receives a placebo
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 following possible confounders would you examine? - CORRECT ANSWER✅✅The severity (stage) of
disease of the patients at the 2 hospitals at baseline
The starting point of the 1 year follow up at both hospitals (after operation vs. after discharge)
