Author Question: A planned quasi-experimental study using a nonequivalent control group design has several extraneous ... (Read 39 times)

s.tung · **on:** Jul 8, 2018

A planned quasi-experimental study using a nonequivalent control group design has several extraneous variables that threaten its internal validity. The nurse researcher's actions should be based on which understanding?

a. The results of the study will not be statistically significant.
b. The random assignment of subjects to groups will nullify the intervening variables.
c. The study should be strengthened by controlling intervening variables.
d. Because observation rather than causation is the purpose of the study, no action is necessary.

Question 2

An after-only nonequivalent control group design would be appropriate to study which of these research questions?

a. What is the effect of the cause of spousal death on widows' self-esteem?
b. What is the effect of preoperative teaching on vascular complications after orthopedic surgery?
c. What is the effect of a mentorship program on improvement of students' clinical performance in a baccalaureate nursing program?
d. What is the effect of a videotaped teaching method on knowledge of adolescent males about the warning signs of testicular cancer?

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

Answer to Question 1

ANS: C

Feedback
A The statistical significance of the study will not necessarily be affected by the extraneous variables.
B By definition, a nonequivalent control group design indicates no random assignment was done. When extraneous variables are identified as threats to the study, they should be controlled using other approaches. For example, if experimental and control groups differ systematically on an important intervening variable (e.g., socioeconomic status), a better match of groups should be attempted.
C Identifying and controlling threats to internal validity will strengthen the study's design.
D Causation is being examined because this is a quasi-experimental study.

Answer to Question 2

ANS: B

Feedback
A A qualitative approach would be appropriate to study the effect of the cause of spousal death on widows' self-esteem.
B After-only nonequivalent control group design is used when outcomes (e.g., vascular complications) cannot be measured before the intervention (e.g., preoperative teaching) and randomization is not used to assign subjects to groups. It makes the assumption that the two groups are equivalent and comparable before the introduction of the intervention.
C Because student performance can be measured before and after the intervention, an after-only approach would not be appropriate.
D Because knowledge of testicular cancer can be measured before and after the intervention, an after-only approach would not be appropriate.