MPharm Master of Pharmacy Master of Pharmacy: Research and Biostatistics 3 — Questions and Answers
Question 1: Which measure of central tendency is most appropriate when data are severely right-skewed, such as drug cost distributions?
- Median (Correct answer)
- Mean
- Mode
- Geometric mean
Correct answer: Median
The median is resistant to extreme values and better represents the 'typical' value in right-skewed distributions like cost data.
Question 2: In pharmacoepidemiology, the 'healthy worker effect' is an example of which type of bias?
- Selection bias (Correct answer)
- Information bias
- Confounding
- Recall bias
Correct answer: Selection bias
The healthy worker effect is a selection bias where employed populations are healthier than the general population, distorting risk estimates.
Question 3: A researcher reports a statistically significant result (p=0.03) with a very small effect size (Cohen's d=0.05). What is the most accurate conclusion?
- The finding is statistically significant but clinically trivial (Correct answer)
- The finding is both statistically and clinically significant
- The finding is clinically significant but statistically marginal
- The p-value is too high to be meaningful
Correct answer: The finding is statistically significant but clinically trivial
With large sample sizes, trivially small differences can reach statistical significance; effect size determines clinical meaningfulness.
Question 4: The area under the ROC curve (AUC-ROC) value of 0.50 for a diagnostic biomarker indicates:
- The biomarker performs no better than random chance (Correct answer)
- The biomarker has perfect discrimination
- The biomarker has moderate discriminative ability
- The biomarker is highly specific but not sensitive
Correct answer: The biomarker performs no better than random chance
An AUC-ROC of 0.50 equals the performance of random chance, meaning the biomarker has no discriminative ability for the condition.
Question 5: In systematic reviews, what does the PRISMA checklist primarily guide?
- Transparent reporting of systematic review methodology and results (Correct answer)
- Statistical analysis of pooled clinical trial data
- Risk of bias assessment within individual studies
- Quality grading of evidence levels
Correct answer: Transparent reporting of systematic review methodology and results
PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) is a reporting guideline to ensure transparency and completeness in systematic review publications.
Question 6: In a crossover pharmacokinetic study, which statistical consideration is most important to address?
- Carry-over effects between treatment periods (Correct answer)
- Baseline imbalance between parallel groups
- Differential dropout rates across arms
- Unequal randomization ratios
Correct answer: Carry-over effects between treatment periods
Crossover studies must include adequate washout periods and statistically test for carry-over effects, as residual drug from period one could confound period two results.
Question 7: Which graphical tool is most appropriate for detecting publication bias in a meta-analysis?
- Funnel plot (Correct answer)
- Forest plot
- Volcano plot
- Bland-Altman plot
Correct answer: Funnel plot
A funnel plot displays effect sizes against standard error; asymmetry suggests small-study effects or publication bias.
MPharm Master of Pharmacy Master of Pharmacy: Research and Biostatistics 3
Which measure of central tendency is most appropriate when data are severely right-skewed, such as drug cost distributions?