NR 503 Midterm Exam Week 4

NR 503 Midterm Exam Week 4 Questions and answers Question 1 Which of the following statements best describe efficacy? 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? Question 3 What is the main advantage of the r&omization of the 168 study participants to one of the two drug treatment groups? 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? 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? 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? Question 7 Which of the following statements best describes the reason for conducting the study as a double- blind trial? 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: 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? 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 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. What is the main purpose of r&omization in this study? Question 11 Test A has a sensitivity of 95% & a specificity of 90%. Test B has a sensitivity of 80% & a specificity of 98%. In a community of 10,000 people with 5% prevalence of the disease, Test A has always been given before Test B. What is the best reason for changing the order of the tests? Question 12 This table represents the results of coronary magnetic resonance (CMR) angiography compared to x-ray angiography (the gold st&ard in diagnosis of coronary artery disease) in a high-risk population of patients scheduled to undergo x-ray angiography for suspected coronary artery disease. After reviewing the results of the test comparison, an epidemiologist decides that the specificity of the test is too low. Using the same CMR images, he raises the cutoff value for a positive test to increase the specificity. What is the likely effect on the sensitivity? Question 13 In comparing the mammography readings of two technicians who evaluated the same set of 600 mammograms for presence of breast cancer from a generally representative sample of women from the population