Question

9.	Which of the following designs would result in the greatest statistical power?
	within-groups (repeated measures) between-groups with matched groups All designs are equal in statistical power. between-groups with random assignment

Answer 1

Repeated measures designs are usually very powerful because they control for factors causing variability between subjects. Hence,

The statistical power for within-groups (repeated measures) would be greatest.

Option A is correct.

Answer 2

The design that would result in the greatest statistical power is:

between-groups with random assignment

Statistical power is the probability of correctly rejecting a null hypothesis when it is false, meaning the probability of detecting an effect if it truly exists. A design with high statistical power is better able to detect small or subtle effects because it minimizes the influence of variability and increases the likelihood of finding a significant result when the effect is present.

In between-groups with random assignment, participants are randomly assigned to different groups, which helps to control for individual differences and confounding variables. This randomization ensures that the groups are comparable at the start of the study, making the design more sensitive to detecting true differences between the groups.

On the other hand, within-groups (repeated measures) and between-groups with matched groups designs can also be powerful, but they may have limitations in terms of controlling for individual differences or confounding variables. All designs can be useful depending on the research question, but in general, between-groups with random assignment is often considered the most robust and powerful design for hypothesis testing in experimental studies.