Statistics Research & Evidence-Based Practice 2

Question 1

A researcher reports a 95% confidence interval of [2.1, 5.8] for a treatment effect. What does this mean?

Accepted Answer

If the study were repeated many times, 95% of such intervals would contain the true parameter

Answer

A 95% CI means that 95% of intervals constructed from repeated samples would contain the true population parameter.

Question 2

Which study design provides the strongest evidence for establishing causation?

Accepted Answer

Randomized controlled trial

Answer

Randomized controlled trials minimize confounding through random assignment, providing the strongest causal evidence.

Question 3

What is the primary purpose of blinding participants in a clinical trial?

Accepted Answer

To reduce placebo and reporting bias

Answer

Blinding prevents participants (and sometimes assessors) from knowing treatment assignments, reducing placebo and reporting biases.

Question 4

In meta-analysis, what does a forest plot primarily display?

Accepted Answer

Effect sizes and confidence intervals from individual studies alongside a pooled estimate

Answer

A forest plot displays individual study effect sizes with their CIs and a pooled overall estimate, enabling visual comparison.

Question 5

A systematic review differs from a narrative review primarily because it:

Accepted Answer

Uses pre-specified, reproducible methods to identify and synthesize evidence

Answer

Systematic reviews use transparent, reproducible search and selection criteria that reduce bias in evidence synthesis.

Statistics Practice Test