NR.210.606 Biostatistics for Evidence Based
Practice
Comprehensive Final Exam (Qns & Ans)
2025
1. Case Scenario:
A nurse practitioner reviews a randomized controlled trial
comparing two antihypertensive agents. The study reports a
p‑value of 0.03 when comparing mean reductions in systolic
blood pressure between groups. Which statement best interprets
this result?
A. There is a 3% chance that the null hypothesis is true.
B. There is a 97% probability that the alternative hypothesis is
true.
C. There is a 3% probability of obtaining the observed difference
(or more extreme) if the null hypothesis were true.
©2025
,D. The study has a Type I error risk of 97%.
Correct ANS: C. There is a 3% probability of obtaining the
observed difference (or more extreme) if the null hypothesis were
true.
Rationale: The p‑value represents the probability of observing
the study’s results (or more extreme) assuming that the null
hypothesis is correct. A p‑value of 0.03 suggests that the result
would occur by chance only 3% of the time, indicating statistical
significance (typically if p < 0.05).
---
2. Case Scenario:
A clinical trial comparing two interventions for reducing HbA1c
in diabetic patients reports a 95% confidence interval for the mean
difference between groups of –0.5 to –0.1. What does this interval
indicate?
A. The true mean difference might be zero.
B. The difference is statistically significant because the interval
does not include 0.
C. There is a 95% probability that the sample mean difference
falls between –0.5 and –0.1.
D. The interventions produce equivalent outcomes.
©2025
, Correct ANS: B. The difference is statistically significant
because the interval does not include 0.
Rationale: A 95% confidence interval that does not cross the
null value (0 for differences) implies that the difference between
groups is statistically significant.
---
3. Case Scenario:
In a hypothesis test set at α = 0.05, a researcher mistakenly rejects
the null hypothesis when it is actually true. This error is known
as:
A. Type I error
B. Type II error
C. Sampling error
D. Measurement error
Correct ANS: A. Type I error
Rationale: A Type I error occurs when the null hypothesis is
rejected even though it is true. The significance level of 0.05
represents the maximum acceptable probability of committing this
error.
©2025
, ---
4. Case Scenario:
A study evaluates the effect of an educational intervention on
patient adherence. Subjects are randomized to either the
intervention or standard care. Which study design is being used?
A. Cross‑sectional study
B. Case‑control study
C. Randomized controlled trial (RCT)
D. Cohort study
Correct ANS: C. Randomized controlled trial (RCT)
Rationale: Randomization with a control group defines an
RCT, which is considered the gold standard for evaluating
causality and minimizing bias.
---
5. Case Scenario:
A regression analysis examining predictors of systolic blood
pressure finds that for each additional year of age, blood pressure
©2025
Practice
Comprehensive Final Exam (Qns & Ans)
2025
1. Case Scenario:
A nurse practitioner reviews a randomized controlled trial
comparing two antihypertensive agents. The study reports a
p‑value of 0.03 when comparing mean reductions in systolic
blood pressure between groups. Which statement best interprets
this result?
A. There is a 3% chance that the null hypothesis is true.
B. There is a 97% probability that the alternative hypothesis is
true.
C. There is a 3% probability of obtaining the observed difference
(or more extreme) if the null hypothesis were true.
©2025
,D. The study has a Type I error risk of 97%.
Correct ANS: C. There is a 3% probability of obtaining the
observed difference (or more extreme) if the null hypothesis were
true.
Rationale: The p‑value represents the probability of observing
the study’s results (or more extreme) assuming that the null
hypothesis is correct. A p‑value of 0.03 suggests that the result
would occur by chance only 3% of the time, indicating statistical
significance (typically if p < 0.05).
---
2. Case Scenario:
A clinical trial comparing two interventions for reducing HbA1c
in diabetic patients reports a 95% confidence interval for the mean
difference between groups of –0.5 to –0.1. What does this interval
indicate?
A. The true mean difference might be zero.
B. The difference is statistically significant because the interval
does not include 0.
C. There is a 95% probability that the sample mean difference
falls between –0.5 and –0.1.
D. The interventions produce equivalent outcomes.
©2025
, Correct ANS: B. The difference is statistically significant
because the interval does not include 0.
Rationale: A 95% confidence interval that does not cross the
null value (0 for differences) implies that the difference between
groups is statistically significant.
---
3. Case Scenario:
In a hypothesis test set at α = 0.05, a researcher mistakenly rejects
the null hypothesis when it is actually true. This error is known
as:
A. Type I error
B. Type II error
C. Sampling error
D. Measurement error
Correct ANS: A. Type I error
Rationale: A Type I error occurs when the null hypothesis is
rejected even though it is true. The significance level of 0.05
represents the maximum acceptable probability of committing this
error.
©2025
, ---
4. Case Scenario:
A study evaluates the effect of an educational intervention on
patient adherence. Subjects are randomized to either the
intervention or standard care. Which study design is being used?
A. Cross‑sectional study
B. Case‑control study
C. Randomized controlled trial (RCT)
D. Cohort study
Correct ANS: C. Randomized controlled trial (RCT)
Rationale: Randomization with a control group defines an
RCT, which is considered the gold standard for evaluating
causality and minimizing bias.
---
5. Case Scenario:
A regression analysis examining predictors of systolic blood
pressure finds that for each additional year of age, blood pressure
©2025
