NR503 Population Health, Epidemiology
& Statistical Principles Exam | Questions
and Verified Answers Rated A+ |
Chamberlain
In the primary analysis of the study, the investigators measured
exposure as a dichotomous variable (any history of STD
compared to no history of STD). In subsequent analyses, the
investigators looked at the relationship between specific STDs
and infertility. They noted the following measures of association:
for past history of gonorrhea, the odds ratio was 2.4 with a 95%
confidence interval of 1.3 to 4.4. For past history of chlamydia, the
odds ratio was 1.8 with a 95% confidence interval from 1.2 to 2.1.
These results indicate that:
- Correct Answer - The odds ratio for chlamydia is more precise
than the odds ratio for gonorrhea
If an investigator is analyzing the results of a clinical trial, then
applying the "intention to treat" rule means that which type of bias
is most likely to result?
- Correct Answer - Misclassification bias
,Investigators wanted to know if some military personnel are more
error prone than others and would be a poor risk for training as a
pilot. A study was done in which individuals who had injuries
during basic training were compared to individuals who had not
had ........ had not had a childhood injury to determine which
group had a higher rate of injuries during basic training. At the end
of follow-up, there was no difference in the rate of injuries
experienced by each group. What type of design was used for the
first study?
- Correct Answer - Case-control
One commanding officer disagreed with this conclusion. He asked
the investigators to design a second study in which all individuals
were asked about childhood injuries prior to the start of basic
training. The group who reported having a childhood injury was
compared to the group who had not had a childhood injury to
determine which group had a higher rate of injuries during basic
training. At the end of follow-up, there was no difference in the
rate of injuries experienced by each group. What type of study
design was used for the second study?
- Correct Answer - Prospective cohort
,Which study better tests the hypothesis that there is a relationship
between childhood injury and subsequent injury during basic
training?
- Correct Answer - Prospective cohort study
Which of the following may explain why the two studies observed
different results concerning the association between childhood
injury and training injury?
- Correct Answer - Potential recall bias in the case-control study
In a study of oral contraceptive (OC) use and hypertension, male
interviewers for the study found a lower prevalence of OC use
among participants than did female interviewers using the same
Questionnaire. Which term best describes this finding?
A matched case-control study of sunscreen use during childhood
and melanoma results in an odds ratio of 1.0. Cases of melanoma
were matched by sex and race to controls who were identified by
, random digit dialing. What is the most likely explanation for the
study's null finding?
- Correct Answer - Information bias concerning past sunscreen
use
Among patients with liver cancer, current alcohol drinkers have a
worse prognosis for survival than nondrinkers. What would be the
impact on the odds ratio for a case-control study of current
alcohol use and liver cancer mortality if prevalent cases were
included with incident cases of the cancer?
- Correct Answer - Decrease the odds ratio when prevalent cases
are included
In a case-control study of maternal cigarette smoking as a risk
factor for low birth weight, the investigators concluded that
mothers of children with low birth weight were more likely to report
smoking during pregnancy relative to mothers of children with
normal birth weight. The reporting error most likely caused the
odds ratio to:
- Correct Answer - Increase above the true value
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