Please explain your answers and show all work, thank you. Part I: Multiple Choic
ID: 3312265 • Letter: P
Question
Please explain your answers and show all work, thank you.
Part I: Multiple Choice 0.2 point each
1. Epidemiologic studies examining the role of a suspected factor in the development of a disease may be observational or experimental. The essential difference between observational and experimental designs is that in experimental designs:
a. The experimental and control groups are equal in size.
b. The experimental study is prospective.
c. The decision for participants to be exposed or not is decided by the study.
d. Controls are used.
2. The following factors are all important in being able to draw appropriate conclusions from a randomized clinical trial. Which is the most important?
a. Equal numbers of treated individuals and those given placebos
b. Follow-up of 100% of the participants
c. Effective randomization of participants
d. A relatively high incidence of the disease in the population studied
e. Inclusion in both groups of individuals of all ages
3. A “double-masked” study of a vaccine is one in which:
a. The experimental group receives the vaccine and the control group receives a placebo.
b. Neither data collectors nor participants know the nature of the placebo.
c. Neither data collectors nor participants know which participant receives the vaccine and which receives a placebo.
d. Neither the experimental group nor the control group knows the identity of the data collectors.
e. The control group does not know the identity of the experimental group.
4. Nonadherence in a randomized controlled trial makes the exposed and unexposed groups more similar, which reduces the ability of the investigator to detect a difference between the groups.
a. True
b. False
5. Researchers are designing a randomized controlled trial (RCT) to test a new treatment for Disease X. They are concerned that smoking could be an important confounder in their RCT, but they may not have a large enough study population to ensure that smoking status is balanced between the intervention and control conditions when they randomize their study population. What else can the investigators do to avoid confounding at the design stage of the study?
a. Match participants on smoking status and then randomize within matched pairs.
b. Develop a protocol to help assure that the loss to follow-up is less than 10%.
c. Compare the crude rate to the smoking-adjusted rate when the study is completed.
d. Compare their crude rate to the smoking-adjusted rate when the study is completed to assess for interaction.
Part II: RCT Study
The Good Behavior Game (GBG) is an evidence-based behavioral classroom management strategy that helps children learn how to work together to create a positive learning environment. GBG is a strong preventive intervention to reduce aggressive, disruptive behavior and increase on-task behavior for early elementary students by the end of first grade, lower the age of first-time smoking for students by middle school, and reduce students’ use of mental health and behavioral services from first grade through young adulthood.
GBG was first tested in 19 elementary schools in Baltimore City1. First-grade classes in each school were randomly assigned to received either GBG or no intervention through the second grade.
6. What was the unit of intervention/analysis? 0.2 point
7. Why was this unit of intervention necessary for this study? 0.2 point
8. The investigators worked with each school principal to make sure that entering first graders were randomly assigned to a GBG or no-GBG classroom. Why was it necessary to assure random assignment? 0.3 point
9. At the end of the study, the investigators observed that GBG did indeed benefit the students in the intervention classrooms, but that the differences were smaller than anticipated. Think about the design of this RCT. What do you think may have happened during the study to decrease the difference between the intervention and control classrooms? How might the study be re-designed to avoid this issue? 0.3 point
Explanation / Answer
1. Epidemiologic studies examining the role of a suspected factor in the development of a disease may be observational or experimental. The essential difference between observational and experimental designs is that in experimental designs:
d. Controls are used.
In an experiment investigators apply treatments to experimental units (people, animals, plots of land, etc.) and then proceed to observe the effect of the treatments on the experimental units.
PS: We are directed to solve only first if multiple questions are posted