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1. Which of the following best defines a p-value in biostatistics?
a. The probability that a study result occurred due to chance alone.
b. The strength of association between two variables.
c. The level of statistical significance required to reject the null
hypothesis.
d. The confidence interval for an odds ratio.
Answer: a. The probability that a study result occurred due to chance
alone.
Rationale: The p-value represents the probability that the observed results
(or more extreme) would occur if the null hypothesis were true. It
provides evidence for or against the null hypothesis and is used to
determine statistical significance.
2. A type II error occurs when:
a. The null hypothesis is incorrectly rejected.
b. The study findings show no significant difference whereas there is one.
c. The study sample size is insufficient to detect a true difference.
d. The p-value is less than 0.05.
Answer: b. The study findings show no significant difference whereas
there is one.
Rationale: A type II error occurs when the null hypothesis is erroneously
accepted, leading to the conclusion that there is no significant difference
between groups, even though there might be one in reality.
3. When conducting a cross-sectional study, which of the following is the
most appropriate measure of association?
a. Relative risk (RR)
b. Odds ratio (OR)
c. Hazard ratio (HR)
d. Pearson correlation coefficient (r)
Answer: b. Odds ratio (OR)
Rationale: Cross-sectional studies examine the relationship between
exposures and outcomes at a specific point in time. As such, odds ratios
(OR) are commonly used to estimate the association between an exposure
and an outcome in this study design
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