NR 503 MIDTERM EXAM –
QUESTION AND ANSWERS
1. Which of the following epidemiological measures is used to describe the frequency of
new cases of a disease in a population over a specific time period? a) Prevalence
b) Incidence
c) Mortality rate
d) Risk ratio
Answer: b) Incidence
● Explanation: Incidence refers to the number of new cases of a disease that develop in a
population during a specified period of time, whereas prevalence refers to the total
number of cases, both new and preexisting.
2. Which study design is best suited for determining the cause-effect relationship
between a risk factor and a disease? a) Cross-sectional study
b) Case-control study
c) Cohort study
d) Randomized controlled trial
Answer: d) Randomized controlled trial
● Explanation: A randomized controlled trial (RCT) is considered the gold standard for
establishing cause-effect relationships because it reduces bias through randomization.
3. What is the primary purpose of public health surveillance? a) To provide health care
services to individuals
b) To monitor health events for planning public health interventions
c) To conduct randomized clinical trials
d) To determine the genetic basis of disease
Answer: b) To monitor health events for planning public health interventions
● Explanation: Public health surveillance involves continuous data collection and analysis
to monitor the health of populations and facilitate timely public health action.
4. A cohort study is conducted to investigate the association between exposure to a
specific chemical and the development of respiratory disease. Which of the following is a
major strength of cohort studies? a) They are inexpensive to conduct
b) They allow for calculation of relative risk
, c) They are effective for rare diseases
d) They do not require a comparison group
Answer: b) They allow for calculation of relative risk
● Explanation: Cohort studies allow researchers to follow exposed and unexposed groups
over time, which enables calculation of the relative risk of developing a disease due to
exposure.
5. Which of the following is NOT a feature of an ecological study? a) It involves data at the
population level
b) It is effective in establishing individual-level associations
c) It is relatively quick and inexpensive to perform
d) It can identify trends across populations
Answer: b) It is effective in establishing individual-level associations
● Explanation: Ecological studies use data at the population level, which makes them
prone to ecological fallacy, as they cannot establish associations at the individual level.
6. Which type of prevention focuses on early detection of diseases to reduce severity
and improve outcomes?
a) Primary prevention
b) Secondary prevention
c) Tertiary prevention
d) Quaternary prevention
Answer: b) Secondary prevention
● Explanation: Secondary prevention aims to detect and treat diseases in the early
stages, thereby reducing severity and preventing further complications.
7. Which of the following best describes the concept of “herd immunity”?
a) Immunity acquired through vaccination
b) A sufficient proportion of the population being immune to a disease
c) Natural immunity gained after infection
d) Immunity passed from mother to child
Answer: b) A sufficient proportion of the population being immune to a disease
● Explanation: Herd immunity occurs when a large portion of the population is immune,
which provides indirect protection to those who are not immune.
8. What is the main focus of the ecological model of health behavior?
a) Individual health behavior
b) Biological risk factors
c) Social and environmental influences
d) Genetic predisposition
QUESTION AND ANSWERS
1. Which of the following epidemiological measures is used to describe the frequency of
new cases of a disease in a population over a specific time period? a) Prevalence
b) Incidence
c) Mortality rate
d) Risk ratio
Answer: b) Incidence
● Explanation: Incidence refers to the number of new cases of a disease that develop in a
population during a specified period of time, whereas prevalence refers to the total
number of cases, both new and preexisting.
2. Which study design is best suited for determining the cause-effect relationship
between a risk factor and a disease? a) Cross-sectional study
b) Case-control study
c) Cohort study
d) Randomized controlled trial
Answer: d) Randomized controlled trial
● Explanation: A randomized controlled trial (RCT) is considered the gold standard for
establishing cause-effect relationships because it reduces bias through randomization.
3. What is the primary purpose of public health surveillance? a) To provide health care
services to individuals
b) To monitor health events for planning public health interventions
c) To conduct randomized clinical trials
d) To determine the genetic basis of disease
Answer: b) To monitor health events for planning public health interventions
● Explanation: Public health surveillance involves continuous data collection and analysis
to monitor the health of populations and facilitate timely public health action.
4. A cohort study is conducted to investigate the association between exposure to a
specific chemical and the development of respiratory disease. Which of the following is a
major strength of cohort studies? a) They are inexpensive to conduct
b) They allow for calculation of relative risk
, c) They are effective for rare diseases
d) They do not require a comparison group
Answer: b) They allow for calculation of relative risk
● Explanation: Cohort studies allow researchers to follow exposed and unexposed groups
over time, which enables calculation of the relative risk of developing a disease due to
exposure.
5. Which of the following is NOT a feature of an ecological study? a) It involves data at the
population level
b) It is effective in establishing individual-level associations
c) It is relatively quick and inexpensive to perform
d) It can identify trends across populations
Answer: b) It is effective in establishing individual-level associations
● Explanation: Ecological studies use data at the population level, which makes them
prone to ecological fallacy, as they cannot establish associations at the individual level.
6. Which type of prevention focuses on early detection of diseases to reduce severity
and improve outcomes?
a) Primary prevention
b) Secondary prevention
c) Tertiary prevention
d) Quaternary prevention
Answer: b) Secondary prevention
● Explanation: Secondary prevention aims to detect and treat diseases in the early
stages, thereby reducing severity and preventing further complications.
7. Which of the following best describes the concept of “herd immunity”?
a) Immunity acquired through vaccination
b) A sufficient proportion of the population being immune to a disease
c) Natural immunity gained after infection
d) Immunity passed from mother to child
Answer: b) A sufficient proportion of the population being immune to a disease
● Explanation: Herd immunity occurs when a large portion of the population is immune,
which provides indirect protection to those who are not immune.
8. What is the main focus of the ecological model of health behavior?
a) Individual health behavior
b) Biological risk factors
c) Social and environmental influences
d) Genetic predisposition
