Why should a nurse researcher attempt to clearly specify exclusion criteria for a study sample?
A) To limit the time needed to complete the study
B) To reduce the effect of extraneous variables on the accurate evaluation of the outcome variable
C) To eliminate the outside influences and inferences regarding the effectiveness of a behavioral intervention
D) To ensure that an adequate sample size is accrued to meet assumptions for accurate statistical analysis

Question

Quizplus · Accepted Answer

Correct B: Exclusion criteria are designed to control sample characteristics and thereby reduce the potential effect of extraneous variables on the outcome variable.
Incorrect A: Exclusion criteria do not directly affect how long a study takes.
Incorrect C: Exclusion criteria delimit the sample but do not fully act as controls for the intervention.
Incorrect D: Sample size is not determined by exclusion criteria.

Why Should a Nurse Researcher Attempt to Clearly Specify Exclusion