Solved by a verified expert:Question 1
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Selection bias is most likely to occur in
which type of study????Answer
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Prospective cohort
studies
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Retrospective cohort
studies
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Case-control studies
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Both retrospective
cohort and case-control studies
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2 points
Question 2
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A case-control study is being conducted
where 10% of the cases and controls actually had the exposure of interest.
However, when asked about the exposure, only 7% of each group recalled the
exposure correctly. This inaccuracy, represented equally between cases and
controls, could be called:???Answer
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Differential
misclassification bias
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Nondifferential
misclassification bias
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Surveillance bias
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Selection bias
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2 points
Question 3
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When assessing the results of a study,
what are the possible explanations for the observed results????Answer
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The observed results
may be due to chance (i.e., random error)
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The observed results
may be true
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The observed results
may be due to bias
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The observed results
may be due to confounding
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The 3rd and 4th
answers only
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The 1st, 3rd, and 4th
answers only
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All of the above
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2 points
Question 4
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If a study fails to detect a significant
difference between treatment A and treatment B when in fact the treatments do
differ, the following type of error has occurred.???Answer
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Type I error
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Type II error
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Treatment
discrimination error
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Difference testing
error
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2 points
Question 5
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Controls are needed in a case-control
study to evaluate whether the frequency of a factor or past exposure among the
cases is different from that among comparable persons who do not have the
disease under investigation.???Answer?True
?False ??
2 points
Question 6
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Controlled clinical trials enable
researchers to:???Answer
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Derive knowledge about
the origins of a disease
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Control the level of
exposure to a treatment
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More accurately
identify cause and effect
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All of the above
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2 points
Question 7
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A case-control study was conducted to
identify risk factors for the common cold. Living with children under the age
of 10 was one of the risk factors evaluated. The odds ratio for this
association was 9.0, and the 95% confidence interval ranged from 1.2 to 85.
Which of the following statements is true about this association????Answer
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People who lived with a
child under the age of 10 had 9 times the risk of getting a cold compared to
people who did not live with children under the age of 10.
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The P value was greater
than 0.05.
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The P value was less
than 0.05.
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The association was
statistically significant.
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The true strength of
association could be estimated more precisely if the study were repeated with
a larger sample.
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The 1st and 2nd answers
only
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The 1st and 3rd answers
only
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The 1st, 3rd, 4th,
and 5th answers only
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The 1st, 2nd, and 5th
answers only
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2 points
Question 8
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What sources can be used to identify
controls for a case-control study????Answer
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General population
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Hospital/clinic
patients
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Friends and relatives
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All of the above
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2 points
Question 9
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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????Answer
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A lower P value
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A greater odds ratio
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A smaller 95%
confidence interval
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A higher disease
prevalence
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The 1st and 3rd answers
only
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The 2nd and 4th
answers only
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The 1st, 2nd, and 3rd
answers only
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All of the above
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None of the above
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2 points
Question 10
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A southwestern state passed a law in 1988
making it illegal to drive without wearing a seat belt. To determine whether
the law had made a difference in terms of mortality, a researcher in the state
health department compiled data on deaths due to vehicle crashes in the 5 years
before 1988 and in the 5 years after 1988. What type of study is this????Answer
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Randomized controlled
trial
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Concurrent cohort study
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Retrospective cohort
study
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Case-control study
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Nested case-control
study
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Cross-sectional study
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Ecologic study
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2 points
Question 11
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Any systematic error in the design or
conduct of a study that results in an incorrect estimate of an exposure’s
effect on the risk of disease is called:???Answer
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Confounding
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Bias
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Stratification
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Effect modification
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2 points
Question 12
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For a variable to be a confounder, it
must be:???Answer
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Associated with the
disease (outcome) under study
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Associated with the
risk factor (exposure) under study
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Both of the above
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Neither of the above
.
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2 points
Question 13
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Which one of the following statements
best describes a limitation of cross-sectional studies????Answer
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No information on
individuals
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Unclear temporal
relationship between exposure and disease
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No comparison group
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2 points
Question 14
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The primary difference between an
experimental and observational study is:???Answer
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The investigator is
“blinded” (prevented from knowing the subjects’ true exposure
status until the end of the study) in an experimental study but not in an
observational study.
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The investigator
controls the subject’s exposure in an experimental study but not in an
observational study.
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The investigator
controls the subject’s outcome in an experimental study but not in an
observational study.
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Experimental studies
are conducted with animals; observational studies are conducted with humans.
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2 points
Question 15
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Over the past 2 years, efforts were made
to identify and determine the mortality and morbidity experience of several
thousand military personnel who were stationed in the Persian Gulf and
elsewhere in Europe in 1991. What type of study is this????Answer
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Case-control study
.
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Prospective cohort
study
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Retrospective cohort
study
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Randomized trial
.
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2 points
Question 16
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A cross-sectional study of the
relationship between blood type and the risk of cataracts will produce
misleading results because you cannot tell the correct temporal relationship
between the exposure (blood type) and disease (cataracts).???Answer?True
?False ??
2 points
Question 17
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Researchers collected baseline
information on oral contraceptive use from a group of female college seniors
from a large university. Each year for the next 20 years, the women were
followed up on to determine whether or not the participants had developed any
of several conditions. What type of study is this????Answer
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Case-control study
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Prospective cohort
study
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Retrospective cohort
study
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Randomized trial
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Cross-sectional study
.
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2 points
Question 18
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The healthy worker effect is a form of
what type of bias????Answer
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Selection bias
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Control-selection bias
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Interviewer/recording
bias
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Surveillance,
diagnostic, or referral bias
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2 points
Question 19
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When chance, bias, and confounding have
been ruled out as alternative explanations for an association, we may conclude
that the association is causal.???Answer?True
?False ??
2 points
Question 20
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Advantages of a case-control design
include all the following except:???Answer
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It is appropriate for
studying rare diseases.
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It is appropriate for
studying rare exposures.
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The odds ratio can
provide an estimate of the relative risk.
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Multiple exposures can
be studied.
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