Which design uses separate groups for each condition with no direct pairing across conditions?

• A. Unrelated design (between groups)
• B. Related design (within subjects)
• C. Matched pairs design
• D. Cross-over design

Answer: (A)

In a between-subjects design, each participant is assigned to only one condition, so there are separate groups for each condition and no participant is directly paired across conditions. This setup yields independent groups, which is exactly what the question describes.

The other designs involve some form of direct pairing or repeated measures: a related or within-subjects design has the same participants experiencing all conditions; matched pairs create pairs of participants who are similar on certain characteristics, with each member exposed to different conditions; a cross-over design has participants going through multiple conditions in sequence (often with washout periods) so observations come from the same individuals across conditions.