CTA Biostatistics & Study Design Flashcards

What is statistical power in a clinical trial?

Answer: The probability of correctly detecting a true treatment effect

Statistical power is the probability that a study will detect a true treatment effect when one actually exists, often set at 80% or higher.

In clinical trials, what does a p-value of less than 0.05 typically indicate?

Answer: The result is statistically significant at the 5% level

A p-value < 0.05 indicates that the observed result would occur less than 5% of the time by chance alone, meeting the conventional threshold for statistical significance.

What is the null hypothesis in a clinical trial?

Answer: The assumption that there is no difference between treatment and control

The null hypothesis assumes no difference between the treatment and control groups, and statistical testing is used to determine whether there is sufficient evidence to reject it.

What is a confidence interval (CI) used for in clinical trial reporting?

Answer: To express the range within which the true treatment effect likely falls

A confidence interval provides a range of plausible values for the true treatment effect, with a 95% CI meaning the true value falls within that range 95% of the time.

What is randomization stratification used for in a clinical trial?

Answer: To ensure balance of key prognostic factors across treatment groups

Stratified randomization ensures that important prognostic factors (such as age or disease severity) are evenly distributed across treatment groups to reduce confounding.

Which analysis population includes all randomized participants regardless of protocol deviations?

Answer: Intent-to-treat (ITT) population

The intent-to-treat (ITT) population includes all randomized participants analyzed in their originally assigned groups, regardless of protocol adherence or withdrawal.