Public Health 150A: Introduction to Epidemiology (part
VI) WELL-ENLIGHTENED.
prospective cohort study correct answers Star$ng in 2013, I assemble a group of healthy
40-‐‐50 year olds who work at UC Berkeley and ask them about their fruit and
vegetable consump$on once a year for 20 years. In 2033 I will review medical records and
record who develops AD and who does not, and compare fruit/veggie consump$on between
groups. THIS IS AN EXAMPLE OF:
case control correct answers I go to a VA Medical Center and find all cases of AD diagnosed
within the last 5 years. I also use the VA records to find non-‐‐AD
individuals and try to match them to cases with respect to age, sex, and race. I contact all of
these people and ask them about their fruit and vegetable consump$on in childhood, age 30,
age 50, and current consump$on. THIS IS AN EXAMPLE OF:
nested case control correct answers At a nursing home, a prospec$ve cohort study of the
effects of healthy ea$ng on weight loss is being conducted. I want to use
this cohort to also study Alzheimer's disease. I iden$fy study par$cipants diagnosed with AD
during this study and match them by $me of diagnosis to controls without AD. THIS IS AN
EXAMPLE OF:
ecologic study correct answers I measure prevalence of AD in 25 countries and compare this
to average fruit and vegetable consump$on of each country.
THIS IS AN EXAMPLE OF:
randomized control trial correct answers I go to a nursing home and randomize everyone to 2
groups: one group will receive meals with considerably more fruits and
vegetables than the second group. AUer 5 years, I plan on tracking development of AD
within each group.
THIS IS AN EXAMPLE OF:
retrospective cohort study correct answers While at the nursing home, I decide to look up
records of people who died within the past year. In the medical records, I can get
a preWy good idea about fruit and vegetable consump$on during their $me in the nursing
home. Using this informa$on, I divide everyone into two groups: high fruit/veggie
consump$on vs. low fruit/veggie consump$on. I then compare the number of
AD diagnoses in each group. THIS IS AN EXAMPLE OF:
beneficence correct answers Which ethical principle would be violated in an RCT if there
was not equipoise with regard to the rela7ve merits of the experimental treatment versus the
current standard of care?
beneficence correct answers this has to do with actually doing no harm.
case control correct answers what istudy is somethign that you can use to quickly and
efficiently identify potential risk factors?
count correct answers an absolute number of anything is known as a _____.
,secondary prevention. correct answers program designed to detect and treat subclinical
carriers is known as: ___ ___.
False (equipoise is somethign that should always be present and is not something that should
need to be maintained) correct answers t/f: masking helps maintain equipose?
true correct answers 2. One of the fundamental differences between a case-control study and
retrospective cohort
is that in a case-control study, the study population is selected based on disease status.
a. True
b. False
C correct answers 3. Total number of births in Sonoma County in the year 2007/
Total number of women ages 16-40 in Sonoma County in the year 2007
a. Rate
b. Proportion
c. Ratio
d. Both B and C
e. None of the above are true
D correct answers 4. Number of persons who reported flu symptoms as part of a national
survey in the year
2009
a. Rate
b. Incidence
c. Prevalence
d. Count
e. None of the above are true
C correct answers 6. All of the following are parts of the epidemiologic triad EXCEPT:
a. Host
b. Vector
c. Population
d. Environment
e. Agent
B correct answers 8. Which of the following is/are TRUE about masking (blinding) in
experimental studies?
a. Masking might prevent study researchers from making accurate measurements
b. Participants often behave differently if they know their treatment status
c. Masking can help maintain equipoised. Masking is only possible for studies of
pharmaceuticals (medicines)
e. Both B and C are true.
D correct answers 9. Which of the disease measures below represent(s) a proportion?
a. Point Prevalence
b. Cumulative Incidence
c. Incidence Density
d. A and B only are true
e. A, B, and C are true
, E correct answers 10. The population of Cedar Lake, Indiana did not change from 2009 to
2010. At any time
during 2009, the number of cases of Oskitis remained steady at about 200. During 2010, the
number of cases was steady at about 250. Which of the following events could have
contributed to the increase from 2009 to 2010?
a. An increase in mortality from Oskitis
b. An increase in the incidence of Oskitis
c. A new treatment that cures Oskitis cases faster
d. A change in the clinical definition of Oskitis
e. Both B and D are true
E correct answers 12. In order to calculate the proportion of students at Flagler College
infected with Lecturean
Sleeping Sickness (LSS), blood samples were collected from a random sample of 350
students during October 2010. What type of study design is best represented by the above
scenario?
a. Randomized Controlled Trial
b. Ecologic
c. Prospective Cohort
d. Case-Control
e. None of the above are true
C correct answers 11. Why is the prevalence of HIV infection in the United States rising?
a. Disease duration has decreased
b. Treatments have not improved
c. Disease duration has increased
d. Disease incidence has decreased
e. Both B and C are true
D correct answers QUESTIONS 14-15 refer to the following study results from a simple
random sample of
Brobdingnagians. The mean height among sampled Western Brobdingnagians is 11.8 meters
and among sampled Eastern Brobdingnagians the mean height is 11.2 meters. The p-value
testing the difference in mean heights is 0.02.
14. Given the null hypothesis that the mean height among Western and Eastern
Brobdingnagians does not differ in the total population, which of the following statements is
MOST accurate?
a. The observed difference in mean sample height is due to chance
b. The probability that the null hypothesis is true is 2%
c. The probability that the null hypothesis is true is < 5%
d. Observing a difference this large would be unlikely if the null hypothesis were true
e. Over many samples, Western Brobdingnagians would be taller in 98% of the samples
B correct answers 16. Investigators want to determine whether the mean SAT score obtained
by 11th grade
students in Bay Area high schools is associated with the proportion of students eligible for
free or reduced lunch benefits at each school.
What type of study design is best represented by the above scenario?
a. Cross-Sectional
VI) WELL-ENLIGHTENED.
prospective cohort study correct answers Star$ng in 2013, I assemble a group of healthy
40-‐‐50 year olds who work at UC Berkeley and ask them about their fruit and
vegetable consump$on once a year for 20 years. In 2033 I will review medical records and
record who develops AD and who does not, and compare fruit/veggie consump$on between
groups. THIS IS AN EXAMPLE OF:
case control correct answers I go to a VA Medical Center and find all cases of AD diagnosed
within the last 5 years. I also use the VA records to find non-‐‐AD
individuals and try to match them to cases with respect to age, sex, and race. I contact all of
these people and ask them about their fruit and vegetable consump$on in childhood, age 30,
age 50, and current consump$on. THIS IS AN EXAMPLE OF:
nested case control correct answers At a nursing home, a prospec$ve cohort study of the
effects of healthy ea$ng on weight loss is being conducted. I want to use
this cohort to also study Alzheimer's disease. I iden$fy study par$cipants diagnosed with AD
during this study and match them by $me of diagnosis to controls without AD. THIS IS AN
EXAMPLE OF:
ecologic study correct answers I measure prevalence of AD in 25 countries and compare this
to average fruit and vegetable consump$on of each country.
THIS IS AN EXAMPLE OF:
randomized control trial correct answers I go to a nursing home and randomize everyone to 2
groups: one group will receive meals with considerably more fruits and
vegetables than the second group. AUer 5 years, I plan on tracking development of AD
within each group.
THIS IS AN EXAMPLE OF:
retrospective cohort study correct answers While at the nursing home, I decide to look up
records of people who died within the past year. In the medical records, I can get
a preWy good idea about fruit and vegetable consump$on during their $me in the nursing
home. Using this informa$on, I divide everyone into two groups: high fruit/veggie
consump$on vs. low fruit/veggie consump$on. I then compare the number of
AD diagnoses in each group. THIS IS AN EXAMPLE OF:
beneficence correct answers Which ethical principle would be violated in an RCT if there
was not equipoise with regard to the rela7ve merits of the experimental treatment versus the
current standard of care?
beneficence correct answers this has to do with actually doing no harm.
case control correct answers what istudy is somethign that you can use to quickly and
efficiently identify potential risk factors?
count correct answers an absolute number of anything is known as a _____.
,secondary prevention. correct answers program designed to detect and treat subclinical
carriers is known as: ___ ___.
False (equipoise is somethign that should always be present and is not something that should
need to be maintained) correct answers t/f: masking helps maintain equipose?
true correct answers 2. One of the fundamental differences between a case-control study and
retrospective cohort
is that in a case-control study, the study population is selected based on disease status.
a. True
b. False
C correct answers 3. Total number of births in Sonoma County in the year 2007/
Total number of women ages 16-40 in Sonoma County in the year 2007
a. Rate
b. Proportion
c. Ratio
d. Both B and C
e. None of the above are true
D correct answers 4. Number of persons who reported flu symptoms as part of a national
survey in the year
2009
a. Rate
b. Incidence
c. Prevalence
d. Count
e. None of the above are true
C correct answers 6. All of the following are parts of the epidemiologic triad EXCEPT:
a. Host
b. Vector
c. Population
d. Environment
e. Agent
B correct answers 8. Which of the following is/are TRUE about masking (blinding) in
experimental studies?
a. Masking might prevent study researchers from making accurate measurements
b. Participants often behave differently if they know their treatment status
c. Masking can help maintain equipoised. Masking is only possible for studies of
pharmaceuticals (medicines)
e. Both B and C are true.
D correct answers 9. Which of the disease measures below represent(s) a proportion?
a. Point Prevalence
b. Cumulative Incidence
c. Incidence Density
d. A and B only are true
e. A, B, and C are true
, E correct answers 10. The population of Cedar Lake, Indiana did not change from 2009 to
2010. At any time
during 2009, the number of cases of Oskitis remained steady at about 200. During 2010, the
number of cases was steady at about 250. Which of the following events could have
contributed to the increase from 2009 to 2010?
a. An increase in mortality from Oskitis
b. An increase in the incidence of Oskitis
c. A new treatment that cures Oskitis cases faster
d. A change in the clinical definition of Oskitis
e. Both B and D are true
E correct answers 12. In order to calculate the proportion of students at Flagler College
infected with Lecturean
Sleeping Sickness (LSS), blood samples were collected from a random sample of 350
students during October 2010. What type of study design is best represented by the above
scenario?
a. Randomized Controlled Trial
b. Ecologic
c. Prospective Cohort
d. Case-Control
e. None of the above are true
C correct answers 11. Why is the prevalence of HIV infection in the United States rising?
a. Disease duration has decreased
b. Treatments have not improved
c. Disease duration has increased
d. Disease incidence has decreased
e. Both B and C are true
D correct answers QUESTIONS 14-15 refer to the following study results from a simple
random sample of
Brobdingnagians. The mean height among sampled Western Brobdingnagians is 11.8 meters
and among sampled Eastern Brobdingnagians the mean height is 11.2 meters. The p-value
testing the difference in mean heights is 0.02.
14. Given the null hypothesis that the mean height among Western and Eastern
Brobdingnagians does not differ in the total population, which of the following statements is
MOST accurate?
a. The observed difference in mean sample height is due to chance
b. The probability that the null hypothesis is true is 2%
c. The probability that the null hypothesis is true is < 5%
d. Observing a difference this large would be unlikely if the null hypothesis were true
e. Over many samples, Western Brobdingnagians would be taller in 98% of the samples
B correct answers 16. Investigators want to determine whether the mean SAT score obtained
by 11th grade
students in Bay Area high schools is associated with the proportion of students eligible for
free or reduced lunch benefits at each school.
What type of study design is best represented by the above scenario?
a. Cross-Sectional
