STP Research Methods 3

Question 1

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

Accepted Answer

Both the participant and the researcher administering/assessing the treatment

Answer

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

Question 2

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

Accepted Answer

Median

Answer

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

Question 3

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

Accepted Answer

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

Answer

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.

Question 4

Ecological fallacy occurs when:

Accepted Answer

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

Answer

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

Question 5

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

Accepted Answer

Type I error

Answer

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

(STP) Scientist Training Programme Practice Test