HSC 404 Final Exam Questions And Answers
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 which of the following?
A lower p value
A greater odds ratio
A smaller 95% confidence interval
A higher disease prevalence
None of the above
An attributable-risk percent of 80% was calculated for the association between smoking and lung
cancer death. Which of the following provides the best interpretation of this statistic?
Of those dying of lung cancer who smoke, 80% of those deaths are attributed to their smoking,
assuming a causal association exists.
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:
The relative risk of the disease in exposed individuals versus unexposed individuals.
and
The prevalence of the exposure in the population.
Several studies have found that approximately 85% of cases of lung cancer are due to cigarette
smoking. This measure is an example of
Attributable risk
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:
Attributable risk
Which of the following is not a method for controlling the effects of confounding in epidemiologic
studies?
Blinding
The purpose of a double-blind study is to
Avoid observer and interviewee bias
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?
All of the above.
In a case-control study of the relationship of radiation exposure and thyroid cancer, 50 cases admitted
for thyroid cancer and 100 "controls" admitted during the same period for treatment of hernias were
studied. Only the cases were interviewed, and 20 of the cases were found to have been exposed to x-
ray therapy in the past, based on the interviews and medical records. The controls were not
, interviewed, but a review of their hospital records when they were admitted for hernia surgery
revealed that only 2 controls had been exposed to x-ray therapy in the past. Based on the description,
what source of bias is least likely to be present in this study?
Bias due to loss of subjects from control groups over time.
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 have thought about confounders such as factor X. This factor X could have confounded your
interpretation of the data if it
Is a factor associated with physical activity and heart disease
In a study to determine the incidence of a 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?
Selection bias: survival bias
Recall bias is most likely to occur in:
Case control studies
An epidemiologic 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
Improve the likelihood that the two groups will be comparable with regard to known and unknown
confounding factors
The strategy which is not aimed at reducing selection bias is
Standardized protocol for structured interviews
Which of the following is not a type of selection bias in cohort studies:
Interviewer bias
The degree of agreement among several trained experts refers to
Inter-judge reliability
A test that determines whether disease is actually present is a
Diagnostic test
A new blood test has been developed to screen for disease Z. Researchers establish 50 units as a cut
point above which a test is considered positive and thereby indicative of disease. The test
manufacturers determine that the test's sensitivity is unacceptably low. However, the manufacturers
are not concerned with the specificity and do not want the cost of the test to rise. How can they
improve the sensitivity of the test?
Lower the cut point below 50 units.
Drs. Poke and Jab (2014) conducted an employee health program that used 5 screening tests at the
same time to detect diseases among workers. Which type of program is this?
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 which of the following?
A lower p value
A greater odds ratio
A smaller 95% confidence interval
A higher disease prevalence
None of the above
An attributable-risk percent of 80% was calculated for the association between smoking and lung
cancer death. Which of the following provides the best interpretation of this statistic?
Of those dying of lung cancer who smoke, 80% of those deaths are attributed to their smoking,
assuming a causal association exists.
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:
The relative risk of the disease in exposed individuals versus unexposed individuals.
and
The prevalence of the exposure in the population.
Several studies have found that approximately 85% of cases of lung cancer are due to cigarette
smoking. This measure is an example of
Attributable risk
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:
Attributable risk
Which of the following is not a method for controlling the effects of confounding in epidemiologic
studies?
Blinding
The purpose of a double-blind study is to
Avoid observer and interviewee bias
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?
All of the above.
In a case-control study of the relationship of radiation exposure and thyroid cancer, 50 cases admitted
for thyroid cancer and 100 "controls" admitted during the same period for treatment of hernias were
studied. Only the cases were interviewed, and 20 of the cases were found to have been exposed to x-
ray therapy in the past, based on the interviews and medical records. The controls were not
, interviewed, but a review of their hospital records when they were admitted for hernia surgery
revealed that only 2 controls had been exposed to x-ray therapy in the past. Based on the description,
what source of bias is least likely to be present in this study?
Bias due to loss of subjects from control groups over time.
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 have thought about confounders such as factor X. This factor X could have confounded your
interpretation of the data if it
Is a factor associated with physical activity and heart disease
In a study to determine the incidence of a 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?
Selection bias: survival bias
Recall bias is most likely to occur in:
Case control studies
An epidemiologic 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
Improve the likelihood that the two groups will be comparable with regard to known and unknown
confounding factors
The strategy which is not aimed at reducing selection bias is
Standardized protocol for structured interviews
Which of the following is not a type of selection bias in cohort studies:
Interviewer bias
The degree of agreement among several trained experts refers to
Inter-judge reliability
A test that determines whether disease is actually present is a
Diagnostic test
A new blood test has been developed to screen for disease Z. Researchers establish 50 units as a cut
point above which a test is considered positive and thereby indicative of disease. The test
manufacturers determine that the test's sensitivity is unacceptably low. However, the manufacturers
are not concerned with the specificity and do not want the cost of the test to rise. How can they
improve the sensitivity of the test?
Lower the cut point below 50 units.
Drs. Poke and Jab (2014) conducted an employee health program that used 5 screening tests at the
same time to detect diseases among workers. Which type of program is this?
