Question 1
Which of the following statements best describe efficacy?
It is an estimate of the benefit of treatment under ideal conditions
It is an estimate of the reduction of disease in treated groups
Question 2
A study is conducted for a pharmaceutical agent that has shown promise for reducing heart disease
among women. In order to more fully test the agent, an additional study is done restricting the
participants to be r&omized to those who have a history of hypertension. Which of the following
advantages cannot be claimed by the researchers?
The generalizability of the study is increased
Question 3
What is the main advantage of the r&omization of the 168 study participants to one of the two drug
treatment groups?
Reduces the potential for selection bias in allocation of treatment group
Question 4
After entry into the study, patients were first classified into three groups, those who had a previous
AMI, those with a first AMI who were at high risk for other cardiovascular diseases such as congestive
heart failure, & those with a first AMI who were at low risk for other cardiovascular diseases. Which
term best describes the study design?
R&omized clinical trial with stratified r&omization
Question 5
After assignment to treatment group, 77% of those in the placebo group were men, while 80% of
those in the drug X group were men. Which statement is most likely to be true?
R&omization was successful since the investigators did not alter the selection of participants in
either group in order to ensure equal percentages of men
Question 6
A preliminary analysis was conducted after 6 months & found that 87% of participants in the placebo
group & 85% of those in the drug X group had taken more than 90% of their prescribed dosages.
Which statement best describes this finding?
, The characteristics of patients who failed to comply with the treatment dosages should be
assessed as they may differ from those who complied
Question 7
Which of the following statements best describes the reason for conducting the study as a double-
blind trial?
Double blinding ensures that potential biases regarding selection, follow-up, & analysis can be
reduced
Question 8
A multicenter double-blind r&omized study was carried out to compare the effect of drug X with that
of a placebo in patients surviving acute myocardial infarction (AMI). Treatment with the drug started
7 days after infarction in 1,884 patients, 52% of all persons who were evaluated for entry into the
study. 945 participants were r&omized to treatment with drug X while 939 were assigned to the
placebo group. Patients were then followed for 12 months for reinfarction. There were 152 deaths in
the placebo group & 98 in the group receiving drug X.
The researchers conclude that treatment with drug X reduces mortality in patients who have had an
AMI. The researchers are:
Correct because the rate of death is decreased in the drug X group
Question 9
The following data come from a study of approaches to smoking cessation. Smokers who want to quit
were r&omized to one of four groups: control group C who received no intervention assistance,
quitting guide group Q who received brochures about how to quit smoking, quitting guide & support
group QS who received quitting brochures as well as social support brochures listing benefits of
smoking cessation, & telephone support group T who received the brochures & a monthly phone call
from a counselor. Participants received mailed surveys at 8, 16, & 24 months after r&omization. The
results after 2 years are in the table below. Which group had the least success in terms of quitting
smoking?
Group QS
Question 10
The following data come from a study of approaches to smoking cessation. Smokers who want to quit
were r&omized to one of four groups: control group C who received no intervention assistance,
quitting guide group Q who received brochures about how to quit smoking, quitting guide & support
Which of the following statements best describe efficacy?
It is an estimate of the benefit of treatment under ideal conditions
It is an estimate of the reduction of disease in treated groups
Question 2
A study is conducted for a pharmaceutical agent that has shown promise for reducing heart disease
among women. In order to more fully test the agent, an additional study is done restricting the
participants to be r&omized to those who have a history of hypertension. Which of the following
advantages cannot be claimed by the researchers?
The generalizability of the study is increased
Question 3
What is the main advantage of the r&omization of the 168 study participants to one of the two drug
treatment groups?
Reduces the potential for selection bias in allocation of treatment group
Question 4
After entry into the study, patients were first classified into three groups, those who had a previous
AMI, those with a first AMI who were at high risk for other cardiovascular diseases such as congestive
heart failure, & those with a first AMI who were at low risk for other cardiovascular diseases. Which
term best describes the study design?
R&omized clinical trial with stratified r&omization
Question 5
After assignment to treatment group, 77% of those in the placebo group were men, while 80% of
those in the drug X group were men. Which statement is most likely to be true?
R&omization was successful since the investigators did not alter the selection of participants in
either group in order to ensure equal percentages of men
Question 6
A preliminary analysis was conducted after 6 months & found that 87% of participants in the placebo
group & 85% of those in the drug X group had taken more than 90% of their prescribed dosages.
Which statement best describes this finding?
, The characteristics of patients who failed to comply with the treatment dosages should be
assessed as they may differ from those who complied
Question 7
Which of the following statements best describes the reason for conducting the study as a double-
blind trial?
Double blinding ensures that potential biases regarding selection, follow-up, & analysis can be
reduced
Question 8
A multicenter double-blind r&omized study was carried out to compare the effect of drug X with that
of a placebo in patients surviving acute myocardial infarction (AMI). Treatment with the drug started
7 days after infarction in 1,884 patients, 52% of all persons who were evaluated for entry into the
study. 945 participants were r&omized to treatment with drug X while 939 were assigned to the
placebo group. Patients were then followed for 12 months for reinfarction. There were 152 deaths in
the placebo group & 98 in the group receiving drug X.
The researchers conclude that treatment with drug X reduces mortality in patients who have had an
AMI. The researchers are:
Correct because the rate of death is decreased in the drug X group
Question 9
The following data come from a study of approaches to smoking cessation. Smokers who want to quit
were r&omized to one of four groups: control group C who received no intervention assistance,
quitting guide group Q who received brochures about how to quit smoking, quitting guide & support
group QS who received quitting brochures as well as social support brochures listing benefits of
smoking cessation, & telephone support group T who received the brochures & a monthly phone call
from a counselor. Participants received mailed surveys at 8, 16, & 24 months after r&omization. The
results after 2 years are in the table below. Which group had the least success in terms of quitting
smoking?
Group QS
Question 10
The following data come from a study of approaches to smoking cessation. Smokers who want to quit
were r&omized to one of four groups: control group C who received no intervention assistance,
quitting guide group Q who received brochures about how to quit smoking, quitting guide & support
