HSC 404, Final Exam Questions and Correct Answers,
With Complete Solution, Updated 2024.
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
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:
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
-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:
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:
attributable risk
Selection bias is most likely to occur in:
both retrospective cohort studies and case control studies
Recall bias is most likely to occur in:
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?
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:
is a factor associated with physical activity and heart disease
The strategy which is NOT aimed at reducing selection bias is:
, Standardized protocol for structured interviews
Which is NOT a method for controlling the effects of confounding in
epidemiological studies?
Blinding
The purpose of a double-blind study is to:
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:
-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:
-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:
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:
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 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
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?
multiphasic screening
Lead time bias is best described as:
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 predictive values?
With Complete Solution, Updated 2024.
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
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:
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
-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:
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:
attributable risk
Selection bias is most likely to occur in:
both retrospective cohort studies and case control studies
Recall bias is most likely to occur in:
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?
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:
is a factor associated with physical activity and heart disease
The strategy which is NOT aimed at reducing selection bias is:
, Standardized protocol for structured interviews
Which is NOT a method for controlling the effects of confounding in
epidemiological studies?
Blinding
The purpose of a double-blind study is to:
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:
-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:
-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:
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:
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 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
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?
multiphasic screening
Lead time bias is best described as:
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 predictive values?
