HSC 404 FINAL EXAM QUESTIONS WITH CORRECT ANSWERS LATEST UPDATE 2026
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 - Answers 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? - Answers 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: - Answers 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 - Answers 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: - Answers Attributable risk
Which of the following is not a method for controlling the effects of confounding in epidemiologic
studies? - Answers Blinding
The purpose of a double-blind study is to - Answers 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? - Answers 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? - Answers 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 - Answers 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? - Answers Selection bias: survival bias
Recall bias is most likely to occur in: - Answers 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 - Answers 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 - Answers Standardized protocol for
structured interviews
Which of the following is not a type of selection bias in cohort studies: - Answers Interviewer bias
The degree of agreement among several trained experts refers to - Answers Inter-judge reliability
A test that determines whether disease is actually present is a - Answers 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? - Answers 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? - Answers Multiphasic
screening
Lead time bias is best described as - Answers An apparently lower survival rate among persons
screened compared to an unscreened group.
A new antibody test detects serum antibodies against virus X (sensitivity 99%, specificity 90%). When
applied in a group of hospitalized patients diagnosed as having virus X infections, the test is found to
have a positive predictive value of 85%. When used to screen a group of healthy blood donors for
virus X infections, the test is found to have a positive predictive value of 30%. Which of the following
best explains this difference between the positive predictive values? - Answers The prevalence of
virus X infection is higher among the hospital patients than among blood donors
The public health officer from Long Beach complains to you about the dreaded Pacific Pox. The health
officer says, "If people catch the Pox, they suddenly get the urge to dance in the sand and fall dead on
the beach within the hour." There are no survivors to interview so you deduce - Answers The case
fatality rate of the Pox must be high.
With respect to a hypothetical rabies investigation conducted among veterinary workers (Dr. Spot,
2003), researchers found that rabies was almost always fatal. This finding refers to - Answers
Virulence
The Centers for Disease Control and Prevention published an article concerning the high rate of foot
fungal disease in New Orleans. The article explains that there has been a high rate of foot fungal
disease in New Orleans for decades. Foot fungal disease in New Orleans is best described as - Answers
endemic
The site where a disease agent enters the body is the - Answers Portal of entry
What factor(s) comprise the epidemiologic triangle - Answers Agent, host, and environment
Someone suggests immunization as a means of reducing disease, specifically the feared UJ (uderlinger
jacamoodi). What part of the disease cycle is he or she trying to affect? - Answers Host
A person with an inapparent infection: - Answers can transmit the infection to others
Asbestos exposure has been associated with - Answers asbestosis, malignant mesothelioma, and lung
cancer
The healthy worker effect - Answers Healthy persons are more likely to gain employment than
unhealthy persons
Synergism - Answers A situation in which the combined effect of several exposures is greater than the
sum of the individual effects
Threshold - Answers The lowest dose at which a particular response may occur
Latency - Answers The time period between initial exposure and a measurable response
It has been suggested that occupational exposure to benzene in the petroleum industry increases the
risk of developing leukemia. The levels of benzene to which workers in this industry have been
exposed were high from 1940 to 1970, but since 1970 have been significantly reduced. What kind of
study design, using petroleum workers, would provide the most useful information on whether
benzene affects incidence rates of leukemia in this industry? You may assume that records of
individual worker assignments to jobs involving benzene exposure have been maintained by the
industry. - Answers Retrospective cohort
Exposure to electric and magnetic fields has been linked to - Answers childhood leukemia risk
Which of the following is the leading source of radiation? - Answers Radon
A sentinel health event refers to - Answers a case of unnecessary workplace disease that serves as a
warning signal
One must use care in interpreting occupational differences in morbidity and mortality because: -
Answers good health status may be a factor for selection into a job
Selye's concept of the general adaptation syndrome did NOT include - Answers stage of recovery
Examples of social incongruity include: - Answers discrepancy between parents in social status
discrepancy between generations, e.g., fathers and sons
changes from rural to urban residence
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 - Answers 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? - Answers 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: - Answers 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 - Answers 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: - Answers Attributable risk
Which of the following is not a method for controlling the effects of confounding in epidemiologic
studies? - Answers Blinding
The purpose of a double-blind study is to - Answers 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? - Answers 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? - Answers 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 - Answers 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? - Answers Selection bias: survival bias
Recall bias is most likely to occur in: - Answers 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 - Answers 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 - Answers Standardized protocol for
structured interviews
Which of the following is not a type of selection bias in cohort studies: - Answers Interviewer bias
The degree of agreement among several trained experts refers to - Answers Inter-judge reliability
A test that determines whether disease is actually present is a - Answers 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? - Answers 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? - Answers Multiphasic
screening
Lead time bias is best described as - Answers An apparently lower survival rate among persons
screened compared to an unscreened group.
A new antibody test detects serum antibodies against virus X (sensitivity 99%, specificity 90%). When
applied in a group of hospitalized patients diagnosed as having virus X infections, the test is found to
have a positive predictive value of 85%. When used to screen a group of healthy blood donors for
virus X infections, the test is found to have a positive predictive value of 30%. Which of the following
best explains this difference between the positive predictive values? - Answers The prevalence of
virus X infection is higher among the hospital patients than among blood donors
The public health officer from Long Beach complains to you about the dreaded Pacific Pox. The health
officer says, "If people catch the Pox, they suddenly get the urge to dance in the sand and fall dead on
the beach within the hour." There are no survivors to interview so you deduce - Answers The case
fatality rate of the Pox must be high.
With respect to a hypothetical rabies investigation conducted among veterinary workers (Dr. Spot,
2003), researchers found that rabies was almost always fatal. This finding refers to - Answers
Virulence
The Centers for Disease Control and Prevention published an article concerning the high rate of foot
fungal disease in New Orleans. The article explains that there has been a high rate of foot fungal
disease in New Orleans for decades. Foot fungal disease in New Orleans is best described as - Answers
endemic
The site where a disease agent enters the body is the - Answers Portal of entry
What factor(s) comprise the epidemiologic triangle - Answers Agent, host, and environment
Someone suggests immunization as a means of reducing disease, specifically the feared UJ (uderlinger
jacamoodi). What part of the disease cycle is he or she trying to affect? - Answers Host
A person with an inapparent infection: - Answers can transmit the infection to others
Asbestos exposure has been associated with - Answers asbestosis, malignant mesothelioma, and lung
cancer
The healthy worker effect - Answers Healthy persons are more likely to gain employment than
unhealthy persons
Synergism - Answers A situation in which the combined effect of several exposures is greater than the
sum of the individual effects
Threshold - Answers The lowest dose at which a particular response may occur
Latency - Answers The time period between initial exposure and a measurable response
It has been suggested that occupational exposure to benzene in the petroleum industry increases the
risk of developing leukemia. The levels of benzene to which workers in this industry have been
exposed were high from 1940 to 1970, but since 1970 have been significantly reduced. What kind of
study design, using petroleum workers, would provide the most useful information on whether
benzene affects incidence rates of leukemia in this industry? You may assume that records of
individual worker assignments to jobs involving benzene exposure have been maintained by the
industry. - Answers Retrospective cohort
Exposure to electric and magnetic fields has been linked to - Answers childhood leukemia risk
Which of the following is the leading source of radiation? - Answers Radon
A sentinel health event refers to - Answers a case of unnecessary workplace disease that serves as a
warning signal
One must use care in interpreting occupational differences in morbidity and mortality because: -
Answers good health status may be a factor for selection into a job
Selye's concept of the general adaptation syndrome did NOT include - Answers stage of recovery
Examples of social incongruity include: - Answers discrepancy between parents in social status
discrepancy between generations, e.g., fathers and sons
changes from rural to urban residence
