70-413 Exam Research & Evidence-Based Practice 3 — Questions and Answers
Question 1: According to the hierarchy of evidence, which source provides the strongest level of evidence for clinical decision-making?
- Expert opinion
- Single randomized controlled trial
- Systematic review with meta-analysis (Correct answer)
- Descriptive study
Correct answer: Systematic review with meta-analysis
Systematic reviews with meta-analysis synthesize findings from multiple high-quality studies, providing the strongest and most reliable evidence at the top of the evidence hierarchy.
Question 2: A 95% confidence interval for a mean difference of 5.2 is reported as (1.4, 9.0). What does this mean?
- The study has 95% statistical power
- We are 95% confident the true mean difference falls between 1.4 and 9.0 (Correct answer)
- 5% of the data falls outside this range
- There is a 5% chance the findings are incorrect
Correct answer: We are 95% confident the true mean difference falls between 1.4 and 9.0
A 95% confidence interval means that if the study were repeated many times, 95% of the calculated intervals would contain the true population mean difference.
Question 3: Which statistic is used in a meta-analysis to represent the combined effect of multiple studies?
- Standard deviation
- Relative risk reduction
- Pooled effect size (Correct answer)
- Cronbach's alpha
Correct answer: Pooled effect size
A pooled effect size (such as a weighted mean difference or odds ratio) combines results from multiple individual studies in a meta-analysis to produce an overall estimate.
Question 4: In evidence-based practice, the acronym PICO stands for:
- Patient, Intervention, Comparison, Outcome (Correct answer)
- Problem, Investigate, Conclude, Optimize
- Protocol, Implement, Control, Observe
- Population, Incidence, Correlation, Outcome
Correct answer: Patient, Intervention, Comparison, Outcome
PICO (Patient/Population, Intervention, Comparison, Outcome) is a framework used to structure clinical questions and guide literature searches in evidence-based practice.
Question 5: Which type of reliability measures the consistency of a test or tool across two administrations to the same group over time?
- Inter-rater reliability
- Internal consistency
- Test-retest reliability (Correct answer)
- Parallel-forms reliability
Correct answer: Test-retest reliability
Test-retest reliability assesses the stability of a measurement instrument by administering the same test to the same participants at two different time points and correlating the scores.
Question 6: A nurse critically appraises a study and notes that patients were not randomly assigned to groups. The study's internal validity is most threatened by:
- Attrition bias
- Selection bias (Correct answer)
- Reporting bias
- Hawthorne effect
Correct answer: Selection bias
Without randomization, pre-existing differences between groups (selection bias) can confound the results, making it unclear whether the intervention or the group differences caused the outcome.
Question 7: Which of the following best describes the concept of 'Number Needed to Treat' (NNT)?
- The number of patients who must receive a treatment for one to be harmed
- The average number of patients required to detect a statistically significant effect
- The number of patients who must be treated to prevent one additional adverse outcome (Correct answer)
- The minimum sample size needed for a study to have adequate power
Correct answer: The number of patients who must be treated to prevent one additional adverse outcome
NNT is a clinical measure indicating how many patients need to receive a treatment to prevent one additional adverse outcome compared to a control group.
70-413 Exam Research & Evidence-Based Practice 3
According to the hierarchy of evidence, which source provides the strongest level of evidence for clinical decision-making?