MCQs in Epidemiology & Biostatistics with Answer Key.

1. 10 MCQs in Epidemiology
Prepared by:
Anish Dhakal (Aryan)

2. 1. Sensitivity of a screening test is the ability to detect positive case results while
specificity is the ability to correctly exclude truly negative cases. A new test
for diagnosis of pulmonary tuberculosis is being developed by scientists with
a high accuracy to correctly differentiate between healthy and unhealthy
cases. They calculated data from a sample and created the following table.
What is the accuracy of the diagnostic test?
Result of test/ True
characteristics
Disease No Disease
Positive 50 5
Negative 10 90
a) 83%
b) 94%
c) 90%
d) 86%

3. 2. A student of a renowned university visited the management team of
the hospital to inform them about a test he thinks is best for forming
treatment protocol of meningitis. When the management inquired
further about the test, they found it very worthless test to spend a
fortune. What statistical parameter might have triggered for such
decision against the test?
a) Positive predictive value = 82%
b) Likelihood ratio = 1
c) Accuracy = 77%
d) Sensitivity = 0.86

4. 3. A person returning from Terai has fever with chills and rigors. Patient
record from National Health report shows that 55% of people returning
from Terai with chills and rigors have malaria. The rapid diagnostic test
for malarial blood smear test shows HRP2 antigen with likelihood ratio
of 8. What is the probability that the person has malaria?
a) 75%
b) 80%
c) 90%
d) 85%

5. 4. Doctors around the world are in dilemma whether to validate a
costly screening test for a particular cancer. A surgeon in a
international conference argued that there is no use of the test since
knowing early about the diagnosis doesn’t improve survival since the
treatment are not yet invented. Which bias is the surgeon tackling
here?
a) Overdiagnosis
b) Omitted variable bias
c) Survivorship bias
d) Lead time bias

6. 5. Following set of data is available for a sample of population in case
control study being tested for a chemical exposure for carcinoma. 43
people were exposed to the chemical while 88 people were not. What
are the odds of the disease occurring due to the exposure?
Result of test/ True
characteristics
Disease No Disease
Positive 8 35
Negative 2 86
a) 9.8
b)8.0
c) 7.1
d)9.1

7. 6. In a cohort study of inflammatory bowel disease, researchers
noted that relative risk of smoking on ulcerative colitis was 0.95.
Which of the following statement is true for the research
finding?
a) Smoking increases risk of ulcerative colitis 9.5 times
b) Non-smokers have 95% less likelihood of getting ulcerative colitis
c) Smoking decreases risk of ulcerative colitis
d) 95% of the cases with ulcerative colitis are smokers

8. 7. For a very rare disease, odds ratio is equal to:
a) Likelihood ratio
b) Positive Predictive value
c) Attributable Risk
d) Relative risk

9. 8. The incidence of lung carcinoma among smokers is 17%. If the
incidence among the sample control population who don’t
smoke is 15%, what is the attributable risk attributes to
smoking?
a) 83%
b) 2%
c) 85%
d) 32%

10. 9. There is still a huge misconception about vaccines in many
communities around the world. Your work is to convince a community
about the benefits of DPT vaccine in preventing pertussis. If 3% of the
patients with vaccine got the disease compared to 15% of children who
didn’t receive the vaccine, what is the relative risk reduction (RRR) that
can be attributed to the vaccine intervention?
a) 80%
b) 20%
c) 5%
d) 45%

11. 10. 10. The sensitivity and specificity of a less useful test for
malaria is 60% and 20% respectively. What is the negative
likelihood ratio of the negative test with disease to negative test
with no disease?
a) 3
b) 4
c) 8
d) 2

12. Answer Key:
1. c
2. b
3. c
4. d
5. a
6. c
7. d
8. b
9. a
10. d