Epidemiology Methods
Multiple Choice Questions
for discussion
•
Taken from the Toronto Notes
• These MCQs do not all follow the current MCC
guidelines (Oops )
March 2013
1
The purpose of randomization is to:
a) make sure that there are equal numbers of men
and women in test and control groups
b) increase the chances of getting a statistically
significant difference
c) ensure that the numbers of cases and controls
are equal
d) limit bias
e) all of the above
March 2013
2
Which of the following types of studies usually
provides only a measure of prevalence?
a) descriptive
b) cross-sectional
c) randomized controlled trial
d) cohort
e) none of the above
March 2013
3
A major advantage of cohort studies over casecontrol studies is that:
a) they take less time and are less costly
b) they can utilize a more representative
population
c) it is easier to obtain controls who are not
exposed to the factor
d) they permit estimation of risk of disease in
those exposed to the factor
e) they can be done on a double-blind basis
March 2013
4
The incidence of a particular disease is greater in men
than in women, but the prevalence shows no sex
difference. The most probable explanation is that:
a) the mortality rate is greater in women
b) the case fatality rate is higher in women
c) the duration of the disease is longer in women
d) women receive less adequate medical care for the
disease
e) this diagnosis is more often missed in women
March 2013
5
March 2013
6
March 2013
7
The following indicate the results of screening
test Q in screening for disease Z :
The specificity of test Q would be:
a) 40/70
b) 120/130
c) 40/50
d) 120/150
e) 40/200
March 2013
8
The positive predictive value would be:
a) 40/70
b) 120/130
c) 40/50
d) 120/150
e) 70/200
March 2013
9
In which of the following study designs is the
odds ratio the statistic typically used to show an
association between cause and effect?
a) a cross sectional/prevalence study
b) a randomized controlled trial
c) a cohort study
d) a case study
e) a case control study
March 2013
10
Alpha error is:
a) the probability of declaring a difference to be
absent when it in fact is present
b) the probability of declaring a difference to be
present when it is not
c) the probability of declaring a difference to be
absent when it is indeed absent
d) the probability of declaring a difference to be
present when it does exist
e) none of the above
March 2013
11
Which one of the following descriptors of a
diagnostic test is influenced by the prevalence of
the disease being tested for:
a) specificity
b) sensitivity
c) accuracy
d) positive predictive value
e) reliability
March 2013
12
Each of the following statements applies to case
control studies EXCEPT:
a) starts with disease
b) suitable for rare diseases
c) relatively inexpensive
d) prolonged follow-up required
e) there may be a problem in selecting and
matching controls
March 2013
13
A clinician who has been examining the patterns of
mortality in your community says that the rates for heart
disease and lung cancer are higher in this community than in
an adjacent community. Which of the following questions
should you ask first?
a) how did the clinician choose the comparison community?
b) have the rates been standardized for age?
c) are tobacco sales significantly different in the two
communities?
d) are the facilities to treat these diseases comparable in the two
areas?
e) are the numbers of deaths comparable in each area?
March 2013
14
The effectiveness of a preventive measure is
assessed in terms of:
a) the effect in people to whom the measure is
offered
b) the effect in people who comply with the
measure
c) availability and the optimal use of resources
d) the cost in dollars versus the benefits in
improved health status
e) all of the above
March 2013
15
Of the five items listed below, the one which
provides the strongest evidence for causality in
an observed association between exposure and
disease is:
a) a large attributable risk
b) a large relative risk
c) a small p-value
d) a positive result from a cohort study
e) a case report
March 2013
16
During a clinical trial, the difference in the success rates
of two drugs was not statistically significant. This
means that:
a) there is no difference in drug effectiveness
b) there is a sizeable probability that the demonstrated
difference in the drugs effectiveness could occur due
to chance alone
c) the demonstrated difference in the drugs effectiveness
is too small to be clinically meaningful
d) the two samples of patients on which the drugs were
tested came from the same population
e) none of the above is true
March 2013
17
All of the following statements about statistical tests are
true EXCEPT:
a) linear regression is used to describe the relationship
between two continuous variables
b) a confidence interval is a range of values giving
information about the precision of an estimate
c) ANOVA tables are used to make comparisons among
the means of 3 or more groups simultaneously
d) in a normal distribution, the mean, median and mode
are equal
e) the chi-square test evaluates the statistical significance
of 2 or more percentages of categorical outcomes
March 2013
18
More MCQs
• Here are some more questions that students
can use to test their own knowledge:
http://www.medicine.uottawa.ca/sim/data/Self
-test_Qs_Epi_Methods_e.htm
• The questions contain comments on the
answers, to illustrate why a given response
is not correct
March 2013
19