HSC 404 Final Exam Questions with Correct Answers Latest Update 2025-2026 Already Passed
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
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: - Answers attributable risk
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 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. The best interpretation of this statistic would be: - Answers Of those dying of lung cancer who
smoke, 80% of those deaths are attributed to their smoking, assuming a causal association exists.
Several studies have found that approximately 85% of cases of lung cancer are due to cigarette smoking.
This is an example of: - Answers attributable risk
Selection bias is most likely to occur in: - Answers both retrospective cohort studies and case control
studies
Recall bias is most likely to occur in: - Answers case control studies
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? - Answers 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 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: - Answers is a factor associated with physical activity and heart disease
, The strategy which is NOT aimed at reducing selection bias is: - Answers Standardized protocol for
structured interviews
Which is NOT a method for controlling the effects of confounding in epidemiological studies? - Answers
Blinding
The purpose of a double-blind study is to: - Answers avoid observer and interviewee bias
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: - Answers -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
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: - Answers -improve the likelihood that the two groups
will be comparable with regard to know and unknown confounding factors
A double-blind study of a vaccine is one in which: - Answers Neither observers nor subjects know which
subject receives the vaccine and which receives a placebo
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 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
Dr.s 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 longer survival time among persons
identified during a screening program because they were identified at an earlier stage of their disease
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 30%. What best explains this difference between the positive
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
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: - Answers attributable risk
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 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. The best interpretation of this statistic would be: - Answers Of those dying of lung cancer who
smoke, 80% of those deaths are attributed to their smoking, assuming a causal association exists.
Several studies have found that approximately 85% of cases of lung cancer are due to cigarette smoking.
This is an example of: - Answers attributable risk
Selection bias is most likely to occur in: - Answers both retrospective cohort studies and case control
studies
Recall bias is most likely to occur in: - Answers case control studies
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? - Answers 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 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: - Answers is a factor associated with physical activity and heart disease
, The strategy which is NOT aimed at reducing selection bias is: - Answers Standardized protocol for
structured interviews
Which is NOT a method for controlling the effects of confounding in epidemiological studies? - Answers
Blinding
The purpose of a double-blind study is to: - Answers avoid observer and interviewee bias
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: - Answers -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
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: - Answers -improve the likelihood that the two groups
will be comparable with regard to know and unknown confounding factors
A double-blind study of a vaccine is one in which: - Answers Neither observers nor subjects know which
subject receives the vaccine and which receives a placebo
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 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
Dr.s 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 longer survival time among persons
identified during a screening program because they were identified at an earlier stage of their disease
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 30%. What best explains this difference between the positive
