Merrill 8th Edition Exam Questions

Introduction to Epidemiology

1. Which of the following best describes the term “efficiency”?
   1. The science and study of the causes of disease and their modes of operation
   2. Ejection of the substance or metabolites from the body
   3. The ability of a program to produce a desired effect among those who participate in the program compared with those who do not
   4. The ability of a program to produce benefits among those who are offered the program
2. The definition of epidemiology involves all of the following, EXCEPT:
   1. identification of determinants.
   2. measuring the distribution of disease.
   3. human populations.
   4. application .
   5. All of these are part of the definition of epidemiology.
3. Which of the following is NOT an activity of descriptive epidemiology?
   1. Monitoring health-related states or events over time
   2. Monitoring potential exposures over time
   3. Evaluating the effects of an assigned intervention on an outcome of interest
   4. Understanding where and when the health problem is greatest
   5. All of these are activities of descriptive epidemiology.
4. A carrier contains, spreads, or harbors an infectious organism. Carriers may have different conditions or states. Which of the following defines a convalescent carrier?
   1. Individual who has been exposed to and harbors a pathogen and who can spread the disease in different places or intervals
   2. Individual who has been exposed to and harbors a pathogen, is in the beginning stages of the disease, is showing symptoms, and has the ability to transmit the disease
   3. Individual who has been exposed to and harbors a pathogen, but has not become ill or shown any of the symptoms of the disease
   4. Individual who has been exposed to and harbors a pathogen and who has done so for some time, but has recovered from the disease
   5. Individual who harbors a pathogen and who, although in the recovery phase of the course of the disease, is still infectious
5. Which of the following is NOT a possible reservoir for pathogens or infectious agents?
   1. Animals or humans
   2. Food
   3. Feces
   4. Organic matter
   5. All of these are possible reservoirs.
6. Which of the following may cause cancer?
   1. H. pylori bacterium
   2. Human papillomavirus
   3. Hepatitis C
   4. Acute sun exposure
   5. All of these have been linked to cancer.
7. The disease-evoking power of a pathogen is called its:
   1. invasiveness.
   2. variability.
   3. virulence.
   4. communicability.
8. The likelihood of a pathogen or agent to be transmitted from one infected person to another susceptible person is referred to as which of the following?
   1. Communicability
   2. Invasiveness
   3. Variability
   4. Virulence
9. What are metabolic diseases?
   1. A collective name that refers to a group of many diseases with one common characteristic: uncontrolled growth of mutated cells.
      • • 1. A lower level of mental, physical, or moral state than is normal
          2. Diseases existing at birth, and often before birth, or that develop during the first month of life
          3. Caused by the body reacting to an invasion of or injury by a foreign object or substance
          4. Any of the diseases or disorders that disrupt the process of converting food to energy on a cellular level. Affects the ability of the cell to perform critical biochemical reactions that involve the processing or transport of proteins (amino acids), carbohydrates (sugars and starches), or lipids (fatty acids)
10. The natural course of communicable disease involves a susceptible host; a point of exposure; a subclinical disease phase; the clinical disease phase; and a phase of recovery, disability, or death. Which phase is related to the incubation period?

Susceptibility phase

Subclinical phase

Clinical disease phase

Recovery, disability, or death phase

11. Active immunity is best described as which of the following?

a. The type of immunity that occurs when the body produces its own antibodies because of a specific invading substance

b. The type of immunity that involves the transfer of antibodies to one person that were produced by another person.

c. The type of immunity that can result from the introduction of already-produced antibodies by another host.

1. Serial surveys involve which of the following?
   1. Ecologic data
   2. Cross-sectional data
   3. Case-control data
   4. Cohort data
2. What study design may be appropriate when it is not possible to estimate an effect on the individual level?
   1. Case series
   2. Cohort
   3. Ecologic
   4. Experimental
3. Public health surveillance refers to which of the following activities?
4. Public health monitoring
5. Interpretation and dissemination of systematically collected data
6. Ongoing collection and analysis of community health data
7. All of these activities are part of public health surveillance.
8. Which of the following descriptive study designs can be useful for generating hypotheses?
9. Ecologic
10. Cross-sectional
11. Case study
12. All of these are correct.
13. The geometric mean for the data 10, 10, 10, 100, 100, 1000, 10000 is:
14. 2.
15. 3.
16. 10.
17. 100.
18. 1000.
19. All of the following are common measures of linear association between two discrete or continuous variables, EXCEPT:
    1. relative risk.
    2. correlation coefficient.
    3. Spearman’s rank correlation coefficient.
    4. regression analysis (slope coefficient).
    5. These are all common measures of linear association between two discrete or continuous variables.
20. The Pearson correlation coefficient between two continuous variables is a potentially misleading measure under what which of the following conditions?

When outliers have a marked effect on the linear curve

When the sample size is large

When both variables involved are normally distributed

All of these can make this measure misleading.

1. Which of the following is a substance that prompts the generation of antibodies and can cause an immune response?
   1. Active immunity
   2. Passive immunity
   3. Antigen
2. How many of the following questions are reflected in descriptive epidemiology?

___ Who?

___ Why?

___ How?

___ What?

___ When?

___ Where?

• 1. 1
  2. 2
  3. 3
  4. 4

1. Who evaluated the Bills of Mortality?
   1. William Farr
   2. John Graunt
   3. Hippocrates
   4. George Soper
2. Who helped to establish the germ theory of disease?
   1. James Lind
   2. John Snow
   3. Louis Pasteur
   4. Florence Nightingale
3. Which of the following lacks independent metabolism?
   1. Bacterium
   2. Fungus
   3. Virus
   4. Parasite
4. What is the mean number of people in the household for the following data?

5.6

5.1

3.8

None of these are correct.

1. True or False? A block-shaped pyramid indicates that the population is having high birth rate and a high death rate.
   1. True
   2. False
2. Suppose in a given region that 15% of its population is younger than 15 and 10% is older than 65 years of age. What would the dependency ratio be?
   1. 36
   2. 50
   3. 46
   4. 33
3. Which of the following best defines a seasonal trend?
4. Represents periodic increases and decreases in the occurrence, interval, or frequency of a health-related state or event
5. Short-term fluctuations, usually brief and unexpected
6. Represents the long-term change in a health-related state or event
7. In the United States, the number of deaths from all causes was 70,663,474 for Whites, 9,692,906 for Blacks, and 1,125,108 for other racial groups for the combined years 2012–2016. The number of cancer deaths during this same time period was 15,533,648 for Whites, 1,946,813 for Blacks, and 249,591 for other racial groups. In which racial group is the proportional mortality ratio lowest?
8. Whites
9. Blacks
10. Other
11. Which of the following statistics is the most appropriate measure to use when investigating a disease outbreak?
    1. Prevalence proportion
    2. Mortality rate
    3. Attack rate
    4. Attributable risk percent
12. An age-adjusted rate is a weighted average of which of the following?
    1. Age-specific rates
    2. Point prevalence proportions
    3. Attack rates
    4. None of these is correct.
13. Suppose eight workers died because of exposure to a toxic chemical. What is the average YPLL for these workers, given their ages at death were 22, 25, 25, 35, 40, 48, 49, and 62 years. Use age 65 years as the endpoint.
14. 222
15. 26.8
16. 214
17. 74.3
18. In a case-control study, misclassification due to recall bias may be termed:
    1. differential.
    2. non-differential.
    3. random.
    4. Two of these are correct.
19. Which of the following is a type of selection bias in case-control studies?
    1. Berkson’s bias
    2. Neyman’s bias
    3. Loss to follow-up
    4. Healthy worker effect
    5. Two of these are correct.
20. How can confounding be controlled at the design level of a case-control study?
    1. Restriction
    2. Multiple regression
    3. Stratification
    4. All of these are ways to control for confounding at the design level.
21. Which study design is appropriate for determining the incidence of disease?
22. Case series
23. Cross-sectional
24. Case control
25. Cohort
26. There are several potential measures that can be used when assessing the association between variables. Which measure is most appropriate for a case-control study?
27. Risk ratio
28. Rate ratio
29. Odds ratio
30. Slope coefficient
31. Correlation coefficient
32. Which of the following is an advantage to using a run-in period in an intervention study?
    1. Increases generalization of the results
    2. Minimizes bias due to loss to follow-up
    3. Reduces bias due to confounding
    4. Reduces bias due to differential recall
33. What is the primary limitation with using a nonrandomized clinical trial?
34. Not effective at controlling for measured confounding variables
35. Not effective at controlling for unmeasured confounding variables
36. Patients may be assigned to an intervention group that they prefer not to be assigned.
37. A comparison group is not available.
38. Which study design focuses on testing preventive measures?
39. Clinical trial
40. Prophylactic trial
41. Therapeutic trial
42. Community trial
43. What would you call an experimental study where the levels of exposure to a presumed cause differ among a population in a way that is relatively unaffected by extraneous factors so that the situation resembles a planned experiment?
44. A natural experiment
45. A within-group design
46. A between-group design
47. A community trial
48. Three principles guide research that involves human participants. These are:
49. respect for persons, beneficence, and justice.
50. confidentiality, compensation, and avoiding harm.
51. explain the meaning of each of these principles.
52. equitable access to benefits of research, moral rightness in action or attitude, and minimizing risk.
53. Which of the following best describes a phase II trial?
    1. Relatively small randomized, blinded trial that tests tolerability and different intensity or dose of the intervention on surrogate or clinical outcomes
    2. Studies involving animals or cell cultures
    3. Relatively large randomized, blinded trial used to evaluate the efficacy of an intervention
    4. An unblinded and uncontrolled study involving a few volunteers to test the safety of an intervention
    5. Large studies (may or may not be a randomized trial) conducted after the therapy has been approved by the FDA to assess the rate of serious side effects and explore further therapeutic uses

For questions 43–46, refer to the following table that reflects population statistics for a hypothetical community.

1. What is the maternal mortality rate?
   1. 229 per 100,000
   2. 836 per 100,000
   3. 700 per 100,000
   4. 26 per 100,000
   5. None of these is correct.
2. What is the infant mortality rate?
   1. 229 per 1,000
   2. 836 per 1,000
   3. 700 per 1,000
   4. 26 per 1,000
   5. None of these is correct.
3. What is the abortion rate?
   1. 25 per 1,000
   2. 84 per 1,000
   3. 70 per 1,000
   4. 26 per 1,000
   5. None of these is correct.
4. What is the cause-specific mortality rate for those who died from heart disease?
   1. 23 per 100,000
   2. 84 per 100,000
   3. 70 per 100,000
   4. 65 per 100,000

Refer to the following data for questions 47–48.

Population A

Age (years) Population # Deaths

15–19 2,000 30

20–24 4,000 50

25–29 4,000 120

Total 10,000 200

Population B

Age (years) Population # Deaths

15–19 2,000 50

20–24 4,000 50

25–29 4,000 60

Total 10,000 160

1. Which of the following is the age-adjusted rate for population B, using population A as the standard?
2. 21 per 1,000
3. 20 per 1,000
4. 16 per 1,000
5. None of these is correct.
6. Which of the following reflects the crude mortality rate ratio for A to B?
7. 1.05
8. 1.25
9. 1.89
10. None of these is correct.

Questions 49–50: In a cohort breast cancer study, a woman is considered to be “exposed” if she first gave birth at age 30 or older. In a sample of 4540 women who gave birth to their first child before the age of 30, 65 developed breast cancer. Of the 1628 women who first gave birth at age 30 or older, 31 were diagnosed with breast cancer.

1. What is the excess risk of breast cancer in those who had their first child at age 30 or older?
   1. 1.2 per 1,000
   2. 3.5 per 1,000
   3. 4.7 per 1,000
   4. None of these is correct.
2. Estimate the percentage of the disease among the exposed that is attributed to the exposure.
   1. 8%
   2. 18%
   3. 25%
   4. 34%
3. If the study design is used to test a specific predetermined hypothesis, then it could be described as which of the following?
4. Descriptive
5. Analytic
6. Cannot be determined with this amount of information
7. Which of the following best describes the null hypothesis?
8. A best guess formulated using a statistic
9. What is currently believed—the status quo
10. An informal basis for a statistical test of association
11. What is the relation between sample size and the P value?
    1. Positive
    2. Negative
    3. None
    4. There may be a positive or negative relation.
12. What can be said of confounding if there is no association between the exposure and purported confounder?
    1. There is a positive confounding effect.
    2. There is a negative confounding effect.
    3. There is no confounding effect.
    4. The confounding effect is influenced by effect modification.
13. In 1856, John Stuart Mill presented three methods of hypothesis formulation in disease etiology: method of difference, method of agreement, and method of concomitant variation. Which of the following best defines method of agreement?
14. The frequency is common to a number of circumstances where the disease occurs at a high frequency.
15. If the frequency of a disease differs between two locations, it may be because a particular factor varies between those two places.
16. A single factor is common to a number of circumstances where the disease occurs at a high frequency.
17. Which of the following is NOT an appropriate way to minimize loss to follow-up?
    1. Exclude those not likely to remain in the study
    2. Have periodic contact with participants
    3. Provide incentives for continued participation
    4. All of these approaches can be used to minimize loss to follow-up.
18. What is the most appropriate type of rate for investigating an outbreak?

a. Incidence density

b. Cumulative incidence

c. Mortality

d. Prevalence proportion

58. When is it appropriate to refer to an epidemic as an outbreak?

a. When the epidemic is localized

b. When the epidemic is widespread

c. When the epidemic is prolonged

d. When you are trying to encourage behavior change

59. Which of the following is a key reason for conducting a cluster investigation?

• 1. Confirm reported disease cases
  2. Identify whether the number of cases is above what is expected
  3. If possible, identify causal relationships
  4. Each of these is a key reason for conducting a cluster investigation.

1. Which of the following best reflects a sentinel event?
2. The occurrences of an unexpected health-related state or event where no clearly recognized cause exists
3. The occurrence of an unexpected health-related state or event that occurs from a specific, recognized cause
4. None of these represents a sentinel event.
5. Which of the following has been linked with Burkitt’s lymphoma?
6. Epstein-Barr virus
7. Human papillomavirus (HPV)
8. H. pylori bacterium
9. Hepatitis B and C viruses
10. What percentage of cases of cancer is lifestyle related?
    1. 10–20%
    2. 30–40%
    3. 50–60%
    4. 80–90%
11. Who is most susceptible to radiation-associated health problems?
12. Elderly
13. Middle aged men and women
14. Young adults
15. Children
16. Which of the following is NOT a risk factor for childhood cancer?
17. Parental exposure to pesticides or chemicals
18. Fetal exposure to solvents
19. Childhood exposure to household chemicals
20. Genetic susceptibility
21. All of these have been linked to childhood cancer.
22. The best study design for studying exposure-disease relationships that involve chronic health-related states or events, when a long latency period is involved, is a(n):
23. cohort study.
24. case-control study.
25. experimental study.
26. community trial.
27. Which of the following best reflects a predisposing factor?
    1. Lack of seat belt use in cars
    2. Societal supports
    3. Immune status
    4. Repeated exposure
28. Which of the following best defines lead-time bias?
29. The screening test looks better than it actually is because younger, healthier people are more likely to get the test.
30. Screening identifies an illness that would not have shown clinical signs before death from other causes.
31. Slow-progressing cases of disease with a better prognosis are more likely to be identified than faster-progressing cases of disease with a poorer prognosis. Thus, cases diagnosed through screening tend to have a better prognosis than the average of all cases.
32. Difference in the time between the date of diagnosis with screening and the date of diagnosis without screening, which, if counted in the survival time of patients, will give a misleading picture of the benefits of treatment
33. Which of the following does NOT describe observation bias?
    1. Differential accuracy of recall between cases and controls
    2. Differential accuracy of exposure information because an interviewer probes cases differently than controls
    3. An uncontrolled extrinsic factor is associated with a disease outcome and independent of that association is also associated with the exposure
    4. All of describe observation bias.

Questions 69–74. A screening test for a newly discovered disease is being evaluated. In order to determine the effectiveness of the new test, it was administered to 900 workers. 150 of the individuals diagnosed with the disease tested positive. A negative test finding occurred in 60 people who had the disease. A total of 50 persons without the disease tested positive for it. Assume the prior probability is not known.

1. What was the sensitivity of the test?
2. 71.4%
3. 74.0%
4. 92.8%
5. 23.3%
6. None of these is correct.

70. What was the specificity of the test?

a. 46.9%

b. 89.3%

c. 92.8%

d. 27.8%

e. None of these is correct.

71. What was the predictive value of a positive test?

a. 71.1%

b. 78.8%

c. 75.0%

d. 53.8%

e. None of these is correct.

72. What was the predictive value of a negative test?

a. 76.7%

b. 91.4%

c. 92.8%

d. 88.8%

e. None of these is correct.

1. What is the overall accuracy of the test?

a. 71.1%

b. 78.8%

c. 75.0%

d. 87.8%

1. What is the prevalence of disease cases in the population?
2. 77%
3. 75%
4. 9%
5. 23%
6. None of these is correct.
7. Which of the following best reflects reliability?
   • • • 1. Measures what it is supposed to measure
         2. Repeatability
         3. Amount in a given time period
8. As an occupational health epidemiologist, you are required to measure the effect of stress on the workers in your manufacturing plant. Two different tests previously developed to measure stress in industrial workers are selected: stress test alpha and stress test delta. The sensitivity and specificity of each test are shown below. Which test generates the greatest proportion of false positives?

Stress Test Alpha Stress Test Delta

Sensitivity 60% 75%

Specificity 95% 90%

• 1. Stress test alpha
  2. Stress test delta

1. In most cases, the study of causality in chronic disease can be best summarized as:
   1. specific.
   2. plausible
   3. multifactorial.
   4. analogous.
2. Consider the situation in a case-control study where the crude odds ratio is 4.6, stratum 1 odds ratio is 1, and stratum 2 odds ratio is 3.0. Which of the following is present?
3. Positive confounding
4. Negative confounding
5. Positive confounding and effect modification
6. Negative confounding and effect modification
7. Confounding but no effect modification
8. Did the Tuskegee syphilis study end up being an experimental study?

a. Yes

b. No

1. What does the area under the ROC curve provide us?
   1. A direct measure of the magnitude of exposure
   2. The yield of a clinical test
   3. The consistency of associated according to specific variation
   4. As estimate of a test’s discriminating ability (also called accuracy).