Research Methods Flashcards

In a double-blind randomized controlled trial, who is unaware of the treatment allocation?

Answer: Both the participant and the researcher administering/assessing the treatment

In a double-blind design, both the participant and the researcher interacting with or assessing them are unaware of group allocation to reduce bias.

Which measure of central tendency is LEAST affected by extreme outliers in a dataset?

Answer: Median

The median is the middle value of a ranked dataset and is not influenced by extreme high or low values, unlike the mean.

A researcher reports a 95% confidence interval of 1.2–3.4 for an odds ratio. What can be concluded?

Answer: The result is statistically significant at p<0.05 because the interval excludes 1

Because the 95% confidence interval for an odds ratio does not include 1 (the null value), the result is statistically significant at the 0.05 level.

Ecological fallacy occurs when:

Answer: Individual-level conclusions are incorrectly drawn from group-level data

Ecological fallacy is the error of applying associations found at the group level to individuals, which may not hold for any given person.

Which type of error occurs when a researcher concludes there IS an effect when in reality there is none?

Answer: Type I error

A Type I error (false positive) is rejecting a true null hypothesis — concluding an effect exists when it does not.

Allocation concealment in an RCT is primarily used to prevent:

Answer: Selection bias during assignment to treatment groups

Allocation concealment hides the upcoming treatment assignment from those enrolling participants, preventing selection bias before randomization.

The number needed to treat (NNT) is calculated as:

Answer: 1 divided by the absolute risk reduction

NNT = 1 / Absolute Risk Reduction, expressing how many patients must be treated to prevent one additional bad outcome.