Which statement describes an independent design?

Which statement describes an independent design?

• A. Treatment conditions use the same participants
• B. Treatments are applied across repeated measures
• C. Data are dependent within groups
• D. Different treatment conditions utilize different organisms, yielding independent data

Answer: (D)

Independent design refers to a between-subjects setup where each participant (or experimental unit) is exposed to only one treatment, so observations in different treatment groups are not related. The statement that different treatment conditions utilize different organisms, yielding independent data, matches this idea because each group comes from a separate set of units, making the data across groups independent. In contrast, using the same participants across treatments or applying treatments in a repeated-measures fashion creates dependence between observations, since the same unit contributes data to multiple conditions. Saying data are dependent within groups also contradicts independence, as it implies observations within a group are linked rather than independent.

Independent design refers to a between-subjects setup where each participant (or experimental unit) is exposed to only one treatment, so observations in different treatment groups are not related. The statement that different treatment conditions utilize different organisms, yielding independent data, matches this idea because each group comes from a separate set of units, making the data across groups independent.

In contrast, using the same participants across treatments or applying treatments in a repeated-measures fashion creates dependence between observations, since the same unit contributes data to multiple conditions. Saying data are dependent within groups also contradicts independence, as it implies observations within a group are linked rather than independent.