FPGEE Biostatistics 3

Question 1

A meta-analysis reports an I² statistic of 75%. How should this be interpreted?

Accepted Answer

75% of the variance in effect sizes is due to heterogeneity rather than chance

Answer

75% of studies found the treatment effective

Answer

The pooled effect size is 0.75

Answer

75% of studies had a low risk of bias

Question 2

Which statistical test is most appropriate to compare median survival times between two independent treatment groups when data are censored?

Accepted Answer

Log-rank test

Answer

Independent samples t-test

Answer

Mann-Whitney U test

Answer

Chi-square test

Question 3

In a crossover clinical trial, what is the primary statistical concern that must be addressed?

Accepted Answer

Carryover effects from the first treatment period

Answer

Observer bias

Answer

Allocation concealment failure

Answer

Loss to follow-up

Question 4

A drug reduces the absolute risk of myocardial infarction from 4% to 1%. What is the relative risk reduction?

Accepted Answer

75%

Answer

3%

Answer

25%

Answer

400%

Question 5

Which of the following best describes a Type II error in hypothesis testing?

Accepted Answer

Failing to reject a false null hypothesis

Answer

Rejecting a true null hypothesis

Answer

Setting alpha too high

Answer

Using a two-tailed instead of one-tailed test

Question 6

A researcher reports a statistically significant result (p = 0.04) with a very large sample (n = 50,000). What additional information is most critical to evaluate clinical relevance?

Accepted Answer

The effect size or clinical magnitude

Answer

The confidence interval width

Answer

Whether a one-tailed test was used

Answer

The degrees of freedom

Question 7

In Kaplan-Meier survival analysis, what does a steeper drop in the survival curve at an early time point indicate?

Accepted Answer

A higher rate of the event occurring early in follow-up

Answer

More censored observations at that time

Answer

Greater survival probability at that time

Answer

A larger standard error