FPGEE Biostatistics 4

Question 1

Berkson's bias is a specific form of selection bias most commonly associated with which study design?

Accepted Answer

Hospital-based case-control studies

Answer

Randomized controlled trials

Answer

Cohort studies

Answer

Cross-sectional studies

Question 2

A study of a new antibiotic uses intention-to-treat (ITT) analysis. Which statement best describes this approach?

Accepted Answer

All randomized patients are analyzed in their originally assigned groups regardless of adherence

Answer

Only patients who completed the full course are analyzed

Answer

Patients are analyzed based on the treatment they actually received

Answer

Dropouts are excluded from the final analysis

Question 3

Which measure of central tendency is most resistant to outliers in a skewed pharmacokinetic dataset?

Accepted Answer

Median

Answer

Mean

Answer

Variance

Answer

Standard deviation

Question 4

A diagnostic test for a rare disease (prevalence 1%) has sensitivity 99% and specificity 99%. What is the approximate positive predictive value?

Accepted Answer

Approximately 50%

Answer

99%

Answer

50%

Answer

1%

Question 5

In multiple linear regression, what does the R² value represent?

Accepted Answer

The proportion of variance in the outcome explained by all predictors combined

Answer

The correlation between each predictor and the outcome

Answer

The statistical significance of each regression coefficient

Answer

The number of predictors in the model

Question 6

A pharmacy researcher performs 20 independent hypothesis tests simultaneously without adjustment. Approximately how many false positives are expected at α = 0.05?

Accepted Answer

1

Answer

0

Answer

5

Answer

10

Question 7

Which nonparametric test is the equivalent of a one-way ANOVA when the normality assumption is violated?

Accepted Answer

Kruskal-Wallis test

Answer

Wilcoxon signed-rank test

Answer

Mann-Whitney U test

Answer

Friedman test