1. What is the purpose of a p-value in hypothesis testing in public health studies? - A) To determine the sample size - B) To assess the probability of observing the data if the null hypothesis is true - C) To calculate the power of the study - D) To estimate the effect size Answer: B) To assess the probability of observing the data if the null hypothesis is true. Rationale: The p-value helps in determining the significance of the results by providing the probability of obtaining the observed results, or more extreme, assuming that the null hypothesis is correct. 2. In a study measuring the association between exercise frequency and hypertension, what type of statistical test would be most appropriate? - A) Chi-square test - B) T-test - C) ANOVA - D) Regression analysis Answer: D) Regression analysis. Rationale: Regression analysis is suitable for examining the relationship between two quantitative variables and can adjust for confounding variables. 3. When evaluating the effectiveness of a new vaccine, which measure would best represent the reduction in risk provided by the vaccine? - A) Relative risk - B) Odds ratio - C) Risk difference - D) Attributable fraction Answer: A) Relative risk. Rationale: Relative risk compares the probability of an event occurring in the exposed group with the unexposed group, making it a clear measure of the vaccine's effectiveness. 4. What does a Kaplan-Meier curve illustrate in public health studies? - A) The distribution of a single variable - B) The relationship between two categorical variables - C) The survival probabilities over time - D) The prevalence of a health condition