A researcher is interested in the relationship between depression and the loss of a loved one. The individuals of interest are bereaved adults and nonbereaved adults. The variables in this study receive no manipulation, and depression is measured in both sets of adults. This is an example of .

A group comparison study

Explanation:

In group comparison study, an experiment compares two groups(the beareaved and nonbeareaved adults in the above study) such as in testing the effects of a treatment where a "comparison group" receives either an alternative treatment or no treatment so that it functions as a source of "counterfactual" causal inference for the purpose of the experiment.

explanation:

with the profits from the european sales, merchants purchased europe's manufactured  goods, including tools and weapons. then the merchants shipped those manufactured  goods, along with the  american  sugar and rum, to west africa where they were bartered for  slaves.

i believe that the answer to the question provided above is that the role of campaign committees is to act as a bridge between state and local campaigns.