Author Question: In a national health study, begun in 2012, thousands of nurses are participating in ongoing research ... (Read 23 times)

wenmo · **on:** Jul 8, 2018

In a national health study, begun in 2012, thousands of nurses are participating in ongoing research to better understand the effects of omega-3 fish oil and Vitamin D-3 upon cardiovascular health and bone health.

Subjects are randomly assigned to experimental or control group, for the two variables. Data about cardiovascular health and bone health is in progress and planned to continue until 2017. This study could be an example of what types of research? (Select all that apply.)
a. Prospective
b. Retrospective
c. Factorial study
d. Event-partitioning
e. Descriptive
f. Correlational
g. Experimental
h. Quasi-experimental

Question 2

A researcher is designing a fully randomized clinical trial. What must a fully randomized clinical trial contain? (Select all that apply.)

a. Random collection of data in both groups
b. Random operationalization of the dependent variable
c. Random assignment to group
d. Random selection
e. Random application of the independent variable

voltaire123 · **Reply #1 on:** Jul 8, 2018

Answer to Question 1

ANS: A, C, G
In retrospective studies, both the proposed cause and the proposed effect have already occurred. In a prospective cohort study, causes may or may not have occurred, but the proposed effect has not. Descriptive and correlational designs are both non-interventional, since they examine variables in natural environments, such as home, and do not include researcher-designed treatments or interventions. Quasi-experimental and experimental designs are both interventional, since they examine the effects of an intervention by comparing differences between groups that have received the intervention and those that have not received the intervention. A merger of the cross-sectional or longitudinal and trend designs, the event-partitioning design, is used in some cases to increase sample size and to avoid the effects of history on the validity of findings. Cook and Campbell referred to these as cohort designs with treatment partitioning. The term treatment is used loosely here to mean a key event that is thought to lead to change. In a descriptive study, the researcher would not cause or manipulate the key event but rather would clearly define it so that when it occurred naturally, it would be recognized. Data across subjects is assumed to be comparable, and a larger sample size would be available for later studies of changes over time. In a factorial design, two or more different characteristics, treatments, or events are independently varied within a single study. This design is a logical approach to examining multicausality.

Answer to Question 2

ANS: C, D
A randomized clinical trial is a planned experiment designed to determine the efficacy of a treatment or independent variable in a study where the experimental group receives the treatment and the control group does not. The research subjects are obtained by random selection. The experimental group and the control group are constituted through random assignment. Then the researcher enacts the independent variable on the experimental group only. In clinical trials, data collection proceeds simultaneously for both groups.