2025 PUBH 8035 FINAL EXAM: UNLOCK THE
SECRETS OF EXPERIMENTAL AND
OBSERVATIONAL RESEARCH. (GRADED A+)
QUESTION 1
Suppose that an experimental study investigator randomized
100 men to the treatment group and 100 men to the
comparison group. However, only 75 men in the treatment
group and 85 men in the comparison group were able
to comply exactly with their assigned regimens. Should the data
analysis be based on the 200 men originally randomized or the
160 men who were able to comply? Choose the best answer.
a. The 200 men who were originally randomized should
be analyzed because the bene ts of randomization will
be preserved.
b. The 160 men should be analyzed because they
represent the true effects of the treatment.
c. The 200 men who were originally randomized should be
analyzed because they represent the entire study
population.
d. The 160 men should be analyzed because they
represent an intent-to-treat analysis.
QUESTION 2
What type of observational study design is best
suited to study a disease that has a long latent
and induction period?
, a. Case-control study
b. Experimental study
c. Cross-sectional study
d. Prospective study
Question 3
Length bias occurs because fast growing tumors are more
likely to be picked up by a screening test than are slow
growing tumors.
True
False
Question 4
Cigarette smoking is a ___________________ of lung cancer.
a.Sufficient cause
b.Necessary cause
c..Both
d.Neither
y
Question 5
A cohort study of co ee drinking and anxiety was conducted
at a university campus. There were a total of 30,000
freshmen who participated. 10,000 were co ee drinkers and
20,000 were not. Of the co ee drinkers, 500 developed
anxiety during the 4 year follow-up period. Of the non-co ee
drinkers, 200 developed anxiety during the same time
period. Assume that no one in the population died or was
lost during the follow-up period. Calculate the risk ratio
(a.k.a. relative risk) using the given data. The numeric value
of the risk ratio is…
SECRETS OF EXPERIMENTAL AND
OBSERVATIONAL RESEARCH. (GRADED A+)
QUESTION 1
Suppose that an experimental study investigator randomized
100 men to the treatment group and 100 men to the
comparison group. However, only 75 men in the treatment
group and 85 men in the comparison group were able
to comply exactly with their assigned regimens. Should the data
analysis be based on the 200 men originally randomized or the
160 men who were able to comply? Choose the best answer.
a. The 200 men who were originally randomized should
be analyzed because the bene ts of randomization will
be preserved.
b. The 160 men should be analyzed because they
represent the true effects of the treatment.
c. The 200 men who were originally randomized should be
analyzed because they represent the entire study
population.
d. The 160 men should be analyzed because they
represent an intent-to-treat analysis.
QUESTION 2
What type of observational study design is best
suited to study a disease that has a long latent
and induction period?
, a. Case-control study
b. Experimental study
c. Cross-sectional study
d. Prospective study
Question 3
Length bias occurs because fast growing tumors are more
likely to be picked up by a screening test than are slow
growing tumors.
True
False
Question 4
Cigarette smoking is a ___________________ of lung cancer.
a.Sufficient cause
b.Necessary cause
c..Both
d.Neither
y
Question 5
A cohort study of co ee drinking and anxiety was conducted
at a university campus. There were a total of 30,000
freshmen who participated. 10,000 were co ee drinkers and
20,000 were not. Of the co ee drinkers, 500 developed
anxiety during the 4 year follow-up period. Of the non-co ee
drinkers, 200 developed anxiety during the same time
period. Assume that no one in the population died or was
lost during the follow-up period. Calculate the risk ratio
(a.k.a. relative risk) using the given data. The numeric value
of the risk ratio is…
