Epidemiology Midterm Exam Practice Questions with 100% Verified Answers Already
Graded A+ | Latest Update 2026/2027 (MOST RECENT!!!)
Which is an example of secondary prevention?
a) Vaccination for rotavirus
b) A screening colonoscopy
c) Antiretroviral therapy for HIV/AIDS
d) Education on wearing a helmet while riding a bike
e) None of the above - Ans - A screening colonoscopy
Which of the following terms is not a way of quantifying prognosis?
a) Case-fatality
b) Disease incidence
c) 5-year survival - Ans - Disease incidence
If we want to ensure balance in the number of individuals allocated to each treatment group, we would use:
a) blinding and randomization
b) block randomization
c) stratified randomization - Ans - block randomization
Match the study design with the correct study description
1|Page
,A study enrolled pregnant women in their first trimester and assessed their diet during the 26-29th week of
pregnancy. Greater adherence to a healthy diet during the second trimester was associated with decreased risk of
preterm birth. - Ans - Cohort
Match the study design with the correct study description
A study assessed cancer mortality from 1996 to 2016 in 133 regions in Brazil. Investigators found that cancer
mortality decreased for regions that had higher government health spending. - Ans - Ecologic
Match the study design with the correct study description
Investigators randomly assigned adults attending a stop-smoking clinic to either nicotine-replacement patches or e-
cigarettes. The primary outcome was sustained abstinence for 1 year. - Ans - Clinical Trial
Match the study design with the correct study description
Subjects over 35 years of age were surveyed about their sleep duration and depressive symptoms. Those who
reported fewer hours of sleep also reported more depressive symptoms. - Ans - Cross-Sectional
Match the study design with the correct study description
Vitamin use during pregnancy in was compared between mothers of infants diagnosed with leukemia and mothers of
infants without leukemia. No association was observed between prenatal vitamins and infant leukemia. - Ans -
Case Control
A randomized trial comparing the efficacy of two drugs did not find a difference between the two drugs (with a P
value > 0.05). Assume that in reality, however, the two drugs do differ. This is an example of :
a) Type I error (alpha)
b) Type II error (beta)
c) 1-alpha
d) 1-beta
e) none of the above - Ans - Type II error (beta)
Describe the differences between active and passive surveillance. - Ans - See notes
2|Page
,A community of 56,000 has the following age and sex distribution within the population at midyear in 2018:
During 2018, there were 600 deaths in the total population with 200 of those due to cancer: 75 in females and 125 in
males. There were 1500 births, 30 fetal deaths, 50 deaths in infants under 28 days, and 25 deaths in infants aged 1
month to 1 year of age.
Referring to the community information, what is the overall infant mortality rate in the community in 2018?
a) 70 per thousand
b) 75 per thousand
c) 50 per thousand
d) 20%
e) none of the above - Ans - 50 per thousand
The ecologic fallacy states that associations observed at the group level will not necessarily be present at the
individual level.
a. True
b. False - Ans - True
Regarding the RAC test, all of the following statements are correct EXCEPT: (See 2 X 2)
a) The specificity of the test was about 12 percent.
b) The false negative rate was about 9 percent.
c) The sensitivity of the test was about 91 percent.
d) The predictive value of a positive result cannot be determined from the information given. - Ans - The
specificity of the test was about 12 percent.
Briefly describe the three main components of the epidemiological triad using West Nile Virus as an example. -
Ans - See notes
Which of the following is not needed to calculate the sample size for a study?
a) the sample p-value
b) the statistical analysis plan
c) the expected differences between the study groups
3|Page
, d) the expected variability of the outcome
e) the desired power (1-beta)
f) the significance level (alpha) - Ans - the sample p-value
Describe crossover in the context of a clinical trial. - Ans - see notes
A founder of medical statistics. - Ans - William Farr
Pioneered clinical trials for vaccination to control the spread of smallpox. - Ans - Edward Jenner
Conducted the first clinical trials that included a concurrently treated control group. - Ans - James Lind
Lobbied for health care reforms and sanitary systems. - Ans - Florence Nightingale
Introduced the terms endemic and epidemic. - Ans - Hippocrates
Suppose that a randomized trial has been performed with proper randomization and that the study is free of biases
and major methodological problems. Given this information, we can conclude that the study is:
a) Externally valid
b) Internally valid
c) Both a and b
d) None of the above - Ans - Internally valid
What is the relationship between incidence and prevalence?
a) prevalence = incidence + duration
b) prevalence = incidence x duration
c) incidence = prevalence + duration
d) duration = prevalence x incidence
e) incidence = prevalence x duration - Ans - prevalence = incidence x duration
The crude mortality rate in Community A was lower than the crude mortality rate in Community B, but the age-
adjusted mortality rate was lower in Community B than in Community A. This indicates that:
a) Investigators made a calculation error
4|Page
Graded A+ | Latest Update 2026/2027 (MOST RECENT!!!)
Which is an example of secondary prevention?
a) Vaccination for rotavirus
b) A screening colonoscopy
c) Antiretroviral therapy for HIV/AIDS
d) Education on wearing a helmet while riding a bike
e) None of the above - Ans - A screening colonoscopy
Which of the following terms is not a way of quantifying prognosis?
a) Case-fatality
b) Disease incidence
c) 5-year survival - Ans - Disease incidence
If we want to ensure balance in the number of individuals allocated to each treatment group, we would use:
a) blinding and randomization
b) block randomization
c) stratified randomization - Ans - block randomization
Match the study design with the correct study description
1|Page
,A study enrolled pregnant women in their first trimester and assessed their diet during the 26-29th week of
pregnancy. Greater adherence to a healthy diet during the second trimester was associated with decreased risk of
preterm birth. - Ans - Cohort
Match the study design with the correct study description
A study assessed cancer mortality from 1996 to 2016 in 133 regions in Brazil. Investigators found that cancer
mortality decreased for regions that had higher government health spending. - Ans - Ecologic
Match the study design with the correct study description
Investigators randomly assigned adults attending a stop-smoking clinic to either nicotine-replacement patches or e-
cigarettes. The primary outcome was sustained abstinence for 1 year. - Ans - Clinical Trial
Match the study design with the correct study description
Subjects over 35 years of age were surveyed about their sleep duration and depressive symptoms. Those who
reported fewer hours of sleep also reported more depressive symptoms. - Ans - Cross-Sectional
Match the study design with the correct study description
Vitamin use during pregnancy in was compared between mothers of infants diagnosed with leukemia and mothers of
infants without leukemia. No association was observed between prenatal vitamins and infant leukemia. - Ans -
Case Control
A randomized trial comparing the efficacy of two drugs did not find a difference between the two drugs (with a P
value > 0.05). Assume that in reality, however, the two drugs do differ. This is an example of :
a) Type I error (alpha)
b) Type II error (beta)
c) 1-alpha
d) 1-beta
e) none of the above - Ans - Type II error (beta)
Describe the differences between active and passive surveillance. - Ans - See notes
2|Page
,A community of 56,000 has the following age and sex distribution within the population at midyear in 2018:
During 2018, there were 600 deaths in the total population with 200 of those due to cancer: 75 in females and 125 in
males. There were 1500 births, 30 fetal deaths, 50 deaths in infants under 28 days, and 25 deaths in infants aged 1
month to 1 year of age.
Referring to the community information, what is the overall infant mortality rate in the community in 2018?
a) 70 per thousand
b) 75 per thousand
c) 50 per thousand
d) 20%
e) none of the above - Ans - 50 per thousand
The ecologic fallacy states that associations observed at the group level will not necessarily be present at the
individual level.
a. True
b. False - Ans - True
Regarding the RAC test, all of the following statements are correct EXCEPT: (See 2 X 2)
a) The specificity of the test was about 12 percent.
b) The false negative rate was about 9 percent.
c) The sensitivity of the test was about 91 percent.
d) The predictive value of a positive result cannot be determined from the information given. - Ans - The
specificity of the test was about 12 percent.
Briefly describe the three main components of the epidemiological triad using West Nile Virus as an example. -
Ans - See notes
Which of the following is not needed to calculate the sample size for a study?
a) the sample p-value
b) the statistical analysis plan
c) the expected differences between the study groups
3|Page
, d) the expected variability of the outcome
e) the desired power (1-beta)
f) the significance level (alpha) - Ans - the sample p-value
Describe crossover in the context of a clinical trial. - Ans - see notes
A founder of medical statistics. - Ans - William Farr
Pioneered clinical trials for vaccination to control the spread of smallpox. - Ans - Edward Jenner
Conducted the first clinical trials that included a concurrently treated control group. - Ans - James Lind
Lobbied for health care reforms and sanitary systems. - Ans - Florence Nightingale
Introduced the terms endemic and epidemic. - Ans - Hippocrates
Suppose that a randomized trial has been performed with proper randomization and that the study is free of biases
and major methodological problems. Given this information, we can conclude that the study is:
a) Externally valid
b) Internally valid
c) Both a and b
d) None of the above - Ans - Internally valid
What is the relationship between incidence and prevalence?
a) prevalence = incidence + duration
b) prevalence = incidence x duration
c) incidence = prevalence + duration
d) duration = prevalence x incidence
e) incidence = prevalence x duration - Ans - prevalence = incidence x duration
The crude mortality rate in Community A was lower than the crude mortality rate in Community B, but the age-
adjusted mortality rate was lower in Community B than in Community A. This indicates that:
a) Investigators made a calculation error
4|Page
